Liquid food composition

ABSTRACT

Provided is a liquid food composition capable of semi-solidifying in the stomach, which is a one-pack type product containing a water-soluble dietary fiber preliminarily added thereto and in the form of a liquid that can be easily taken, and stably sustains the liquid nature thereof during distribution and storage. The liquid food composition, which is capable of semi-solidifying in an acidic region, comprises a water-soluble dietary fiber (a), a specific metal compound (b), a protein (c) and an emulsifier (d), and the particle size distribution of particles contained in said liquid food composition shows two or more peaks in a neutral region.

TECHNICAL FIELD

The present invention relates to a liquid food composition that is used,for example, by elderly people, people with disease, patients before andafter surgery, healthy people, and the like for taking nutrients.

BACKGROUND ART

For elderly people and patients with disease or before and after surgerywho cannot take food orally, a tube feeding method is used fornutritional support. The tube feeding method includes a method ofadministering intravenously nutrition and a method of administeringenterally nutrition into the alimentary canal. It is believed that theenteral nutrition is desirably used when the administration to thealimentary canal can be performed because, for example, the enteralnutrition does not require strict aseptic handling and bowel functioncan be maintained as compared with the intravenous administration. Inthe enteral nutrition, the administration is often performed through anasogastric tube, a gastrostomy tube, or the like. For such anadministration, liquid nutrition foods are typically used. However, itis known that the use of the liquid nutrition food may causegastroesophageal reflux disease, aspiration pneumonia, diarrhealdisease, leakage from a fistula, or the like because the nutrition foodis a liquid. As a measure of such a problem, there are reports thatsemi-solidification of a nutrition food or a nutrition food having ahigher viscosity is effective. However, such measures can notsufficiently solve the problems because, for example, such a food needsa certain amount of time for preparation or a certain amount of forcethat continues to be applied for pushing out the nutrition food duringtube feeding.

As means for solving these problems, there are disclosed, for example, agelling agent containing a gellan gum and alginic acid and a tubefeeding nutrition food containing the gelling agent (Patent Document 1)as well as an enteral nutrient using carrageenan in sodium form as asemi-solidifying agent (Patent Document 2). These inventions intend toprevent the problems by adding, to a liquid food, the gellan gum, thecarrageenan, or the like for gelation (semi-solidification) of theliquid food. These gelation techniques for liquid foods are consideredto be also effective for the relief of the feeling of hunger, thesuppression of sudden increase in blood glucose level, and the like andinventions relating to the applications of such a technique to a dietfood and a food for diabetes are also disclosed (Patent Documents 3 to5).

However, it is supposed that there is still room for improvement inthese conventional gelation techniques for liquid foods from theviewpoints of the change in physical properties due to dilution of food,easiness in food intake, stability of food during storage, a nutritionalviewpoint of food, and the like. For example, in the tube feedingnutrition food disclosed in Patent Document 1, a gelling agentsimultaneously containing a gellan gum and alginic acid is added to atube feeding nutrition food. However, after the gelling agent is addedto the tube feeding nutrition food, water is required to be furtheradded, and such preparation takes some time and effort. In addition, thefood after preparation is diluted by the amount of the gelling agentadded and hence may have greatly altered physical properties from thoseof the original tube feeding nutrition food. In Patent Document 2,carrageenan is added to a food as a semi-solidifying agent, and the foodis semi-solidified in a short period after preparation. Thus, even whena prepared food has flowability capable of tube feeding, it requires acertain amount of force for passing through a tube because it has a highviscosity and may cause tube clogging. Hence, such a food is notnecessarily easily taken. Furthermore, in these techniques (PatentDocuments 1 and 2), when the gelling agent or the semi-solidifying agentis preliminarily mixed in a food, the food is solidified with time.Thus, the gelling agent such as a water-soluble dietary fiber is addedto a food immediately before intake. Therefore, the techniques are atechnique in which two liquids are mixed for use and do not provide aone-pack type product in which a gelling agent is preliminarily mixed ina food.

Patent Document 3 discloses a technique relating to a diet food and afood for diabetes utilizing that a simple composition composed ofalginic acid and a calcium compound insoluble in a neutral conditionchanges into a gel when the composition is in contact with gastricjuice. However, the water-soluble dietary fiber such as alginic acid maycause component separation such as phase separation when such a fiber ismixed with protein. No protein is actually mixed in Patent Document 3.The technique in Patent Document 3 is a technique for providing a dietfood and a food for diabetes. There is no description relating to amethod for adding mineral components other than a calcium compound andthe effect is not studied. However, mineral components other than acalcium compound are important mineral components for humans and acomposition without mineral components other than the calcium compoundis not a nutritionally satisfactory composition. Furthermore, thetechnique disclosed in Patent Document 3 may cause problems. Forexample, in the preparation of an enteral nutrition food that is takenby, for example, elderly people and patients with disease or before andafter surgery who cannot take food orally or of a nutrition foodcontaining many components such as protein and mineral components,physical properties may be impaired during preparation or storage andnutrient components may be separated during storage.

Patent Document 4 relates to a composition that is liquid at aroundneutral pH and that forms an adhesive matrix at low pH. The compositionincludes (a) at least 0.05 wt % of pectin having a degree ofmethoxylation of 2 to 50 and/or of alginate, (b) at least 5 mg ofcalcium per 100 ml, and (c) at least 0.1 wt % of indigestibleoligosaccharide having a degree of polymerization of 2 to 60 asessential components and includes digestible carbohydrates, lipids, andplant proteins such as a soybean as optional components. Patent Document5 relates to a food composition having enhanced satiety effect. The foodcomposition includes at least 1 wt % of protein and 0.1 to 5 wt % of abiopolymer thickening agent (for example, pectin and alginate) that isnot denatured or hydrolyzed between pH 2 and 4 as essential components.The food compositions described in these patents have an effect ofobtaining higher viscosity in the stomach to enhance satiety effect.However, the present inventors have studied to reveal that a foodcomposition prepared by mixing raw materials described in these patentscauses problems of generating aggregates during preparation and/orstorage. When such aggregates have been generated, tube feeding of theprepared composition has caused a problem of tube clogging due to theaggregates present in the liquid food composition (especially a throttlefor controlling feeding speed has been clogged with the aggregates).Furthermore, the liquid food composition has obtained a high viscositydue to the presence of the aggregates to result in poor tube passageperformance of the liquid food composition. Moreover, for oral intake ofthe prepared composition, the presence of the aggregates has increased“granular texture” and the presence of the aggregates has increased theviscosity to greatly impair “swallowing feeling”. Therefore, theconventional liquid food composition that is semi-solidified in anacidic region has been very difficult to be used.

CITATION LIST Patent Literatures

-   Patent Document 1: JP-A No. 2000-169396-   Patent Document 2: International Publication WO 2006/041173-   Patent Document 3: JP-A No. 4-23968-   Patent Document 4: JP-A No. 2005-513077-   Patent Document 5: JP-A No. 2007-503823

SUMMARY OF INVENTION Technical Problem

As described above, the conventional gelation technique for liquid foodsis insufficient from the viewpoints of the change in physical propertiesof food due to the dilution of food, easiness in food intake, stabilityof food during storage, and the like and there is a demand for a moresatisfactory liquid food composition.

In view of the above circumstances, it is an object of the presentinvention to provide a liquid food composition that is semi-solidifiedin the stomach and preliminarily contains a water-soluble dietary fiberand that is in the form of a liquid, is easily taken, stably sustainsthe liquid nature of the composition during preparation and even duringdistribution and storage, and also, is unlikely to cause clogging in atube and has good tube passage performance at the time of tube feeding,has less “granular texture” and good “swallowing feeling” at the time oforal intake, and is consequently easily taken.

Solution to Problem

In order to solve the problems, the present inventors have carried outintensive studies, for example, on the selection of components in afood. As a result, the inventors have found that by mixing awater-soluble dietary fiber such as alginic acid and a salt thereof, ametal compound containing a necessary mineral component for humans andnot causing gelation of the water-soluble dietary fiber in a neutralregion, such as a calcium compound having poor solubility and amagnesium compound having poor solubility, a plant protein such as asoybean protein and a hydrolysate thereof, and an emulsifier such aslysolecithin and sucrose laurate and by controlling the particle sizedistribution of a liquid food composition containing these components, aliquid food composition that is semi-solidified in an acidic conditionin the stomach can be provided and the liquid food composition is (1) acomposition preliminarily containing the water-soluble dietary fiber,(2) in the form of a liquid and is easily taken, (3) stably sustains theliquid nature even during distribution and storage, (4) does notgenerate aggregates, and (5) can satisfy nutritional requirements, andthe present invention has been accomplished.

That is, the present invention relates to

(1) a liquid food composition being semi-solidified in an acidic region,the liquid food composition comprising

a water-soluble dietary fiber (a),

a metal compound (b) containing a necessary mineral component for humansand not causing gelation of the water-soluble dietary fiber in a neutralregion,

a protein (c), and

an emulsifier (d),

the liquid food composition including particles having a particle sizedistribution with two or more peaks in the neutral region;

(2) the liquid food composition according to the item (1), in which theliquid food composition in a semi-solidified state has a viscosity of1,000 cP or more in the acidic region;

(3) the liquid food composition according to the item (2), in which atleast one of two or more peaks present in the particle size distributionof the particles is present at a particle size of 3,000 nm or smaller;

(4) the liquid food composition according to any one of the items (1) to(3), in which ultrasonic treatment of the liquid food compositionincreases a frequency of the at least one peak present at a particlesize of 3,000 nm or smaller after the ultrasonic treatment as comparedwith that before the ultrasonic treatment and reduces a frequency of atleast one peak other than the peak having the increased frequency afterthe ultrasonic treatment as compared with that before the ultrasonictreatment;

(5) the liquid food composition according to any one of the items (1) to(4), in which, in the at least one peak having the increased frequencyin the particle size distribution of particles after the ultrasonictreatment, the increased frequency is 105% or more with respect to thefrequency in the particle size distribution of particles before theultrasonic treatment and, in the at least one peak having the reducedfrequency in the particle size distribution of particles after theultrasonic treatment, the reduced frequency is 60% or less with respectto the frequency in the particle size distribution of particles beforethe ultrasonic treatment;

(6) a liquid food composition being semi-solidified in an acidic region,the liquid food composition comprising

a water-soluble dietary fiber (a),

a metal compound (b) containing a necessary mineral component for humansand not causing gelation of the water-soluble dietary fiber in a neutralregion,

a protein (c), and

an emulsifier (d),

the liquid food composition having a distribution curve of two or moreinflection points, when representing a particle size distribution ofparticles included in the liquid food composition in the neutral region,as a distribution curve of a passing particle integrated value based onvolume;

(7) the liquid food composition according to the item (6), in which theliquid food composition in a semi-solidified state has a viscosity of1,000 cP or more in the acidic region;

(8) the liquid food composition according to the item (7), in which atleast one of the inflection points in the distribution curve is presentin a particle size section having a particle size of 3,000 nm orsmaller;

(9) the liquid food composition according to any one of the items (6) to(8), in which at least one of the inflection points in the distributioncurve is present in a particle size section having a particle size of2,000 nm or smaller, and ultrasonic treatment of the liquid foodcomposition increases a passing particle integrated value correspondingto the at least one inflection point, present in a particle size sectionhaving a particle size of 2,000 nm or smaller, by 5% or more after theultrasonic treatment as compared with that before the ultrasonictreatment;

(10) the liquid food composition according to any one of the items (6)to (9), in which at least one of the inflection points in thedistribution curve is present in a particle size section having aparticle size of 2,000 nm or smaller, and ultrasonic treatment of theliquid food composition shifts a passing particle integrated valuecorresponding to the at least one inflection point, present in aparticle size section having a particle size of 2,000 nm or smaller, toa section having a passing particle integrated value of 25% or moreafter the ultrasonic treatment as compared with that before theultrasonic treatment;

(11) the liquid food composition according to any one of the items (1)to (10), in which aggregate weight determined by a measurement methodbelow is 0.1 g or less,

aggregate weight: 200 ml of the liquid food composition is filteredusing a 264-mesh nylon screen of which dry weight (W1) is preliminarilyweighed; the nylon screen after the filtration is dried at 60° C. for 1hour and then cooled; a dry weight (W2) of the screen is weighed; anddifference (W2−W1) between the dry weights before and after thefiltration is calculated to determine weight of an aggregate obtained asa residue;

(12) the liquid food composition according to any one of the items (1)to (11), in which the water-soluble dietary fiber (a) is alginic acidand/or a salt thereof,

(13) the liquid food composition according to any one of the items (1)to (12), in which the protein (c) is a plant protein derived from aplant;

(14) the liquid food composition according to the item (13), in whichthe plant protein is a bean-derived protein;

(15) the liquid food composition according to the item (14), in whichthe bean-derived protein is a soybean protein and/or a hydrolysatethereof;

(16) the liquid food composition according to any one of the items (1)to (15), in which the metal compound (b) containing a necessary mineralcomponent for humans and not causing gelation of the water-solubledietary fiber in the neutral region is at least one compound selectedfrom the group consisting of a metal compound having poor solubility inthe neutral region, a metal compound included in a microorganism such asa yeast, and a metal compound included in a microcapsule;

(17) the liquid food composition according to the item (16), in whichthe metal compound (b) containing a necessary mineral component forhumans and not causing gelation of the water-soluble dietary fiber (a)in the neutral region is a calcium compound having poor solubility inthe neutral region and/or a magnesium compound having poor solubility inthe neutral region;

(18) the liquid food composition according to the item (17), in whichthe calcium compound (b) having poor solubility in the neutral region isat least one compound selected from the group consisting of calciumcitrate, calcium carbonate, calcium dihydrogen pyrophosphate, tricalciumphosphate, calcium monohydrogen phosphate, calcium stearate, and calciumsilicate;

(19) the liquid food composition according to the item (17), in whichthe magnesium compound (b) having poor solubility in the neutral regionis at least one compound selected from the group consisting of magnesiumcarbonate, magnesium oxide, magnesium stearate, and trimagnesiumphosphate;

(20) the liquid food composition according to the item (16), in whichthe metal compound (b) containing a necessary mineral component forhumans and not causing gelation of the water-soluble dietary fiber (a)in the neutral region is at least one selected from the group consistingof a zinc-containing yeast, a copper-containing yeast, amanganese-containing yeast, a chromium-containing yeast, aselenium-containing yeast, and a molybdenum-containing yeast;

(21) the liquid food composition according to the item (16), in whichthe metal compound (b) containing a necessary mineral component forhumans and not causing gelation of the water-soluble dietary fiber (a)in the neutral region is ferric sodium citrate;

(22) the liquid food composition according to any one of the items (1)to (21), in which the emulsifier (d) is an emulsifier having an HLBvalue of more than 9;

(23) the liquid food composition according to the item (22), in whichthe emulsifier (d) is lysolecithin and/or a sucrose fatty acid estercomposed of a fatty acid monoester having a carbon number of 18 or less;

(24) the liquid food composition according to the item (22) or (23), inwhich the emulsifier (d) is lysolecithin and/or sucrose laurate;

(25) the liquid food composition according to any one of the items (1)to (24), further including a fat (e);

(26) the liquid crystal food composition according to the item (25), inwhich the emulsifier (d) and the fat (e) are mixed in a ratio ((d)/(e),based on weight) of more than 5/100 and 30/100 or less;

(27) the liquid food composition according to any one of the items (1)to (26), in which at least the components (a) to (d) are filled in acontainer as a one-pack type product;

(28) the liquid food composition according to any one of the items (1)to (27), further including a nutrient component (f);

(29) the liquid food composition according to any one of the items (1)to (28), sustaining a liquid state during storage;

(30) the liquid food composition according to any one of the items (1)to (29), in which the liquid food composition is semi-solidified in anacidic environment in a stomach and has an effect of preventinggastroesophageal reflux disease, aspiration pneumonia, diarrhealdisease, leakage from a fistula, or the like;

(31) the liquid food composition according to any one of the items (1)to (30), in which the liquid food composition is semi-solidified in anacidic environment in a stomach and has an effect of relieving thefeeling of hunger;

(32) the liquid food composition according to any one of the items (1)to (31), in which the liquid food composition is semi-solidified in anacidic environment in a stomach and has an effect of suppressing suddenincrease in blood glucose level;

(33) an enteral nutrition food including the liquid food compositionaccording to any one of the items (1) to (32);

(34) an oral nutrition food including the liquid food compositionaccording to any one of the items (1) to (32); and

(35) a diet food including the liquid food composition according to anyone of the items (1) to (32).

Advantageous Effects of Invention

The liquid food composition that is semi-solidified in an acidiccondition of the present invention as described above preliminarilyincludes a water-soluble dietary fiber and hence eliminates the time andeffort for adding a gelling agent and the like at the time of intake. Inaddition, the liquid food composition can be easily taken because it isliquid. The liquid food composition of the present invention can stablysustain quality of the composition during preparation and even duringdistribution and storage for a long time, and hence the liquid foodcomposition that is semi-solidified in an acidic condition can bepractically supplied. The present invention can also provide a novelliquid food composition that has a nutritionally satisfactoryformulation by containing, for example, necessary mineral components forhumans, such as calcium, and a plant protein such as a soybean proteinwhile providing the advantages above. In particular, the liquid foodcomposition can suppress the generation of aggregates during preparationand/or storage of the composition. Therefore, the present invention canprovide a liquid food composition that is unlikely to cause clogging ina tube and has good tube passage performance at the time of tubefeeding, has less “granular texture” and good “swallowing feeling” atthe time of oral intake, and is consequently easily taken.

The liquid food composition according to the present invention can beused for an enteral nutrition food and an oral nutrition food by takingthe advantages and can be used for, for example, a nutrition food, anenteral nutrition food, an enteral nutrient including a diet classifiedas a medicinal supplies, an elemental diet, a polymeric formula, anoligomeric formula, a high density liquid diet, a diet food, and a foodfor diabetes.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Example 1 and FIG. 1( b) is afigure showing the particle size distribution of particles in the liquidfood composition of Example 1 as a distribution curve where verticalaxis is passing particle integrated value (%) based on volume.

FIG. 2( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Example 3 and FIG. 2( b) is afigure showing the particle size distribution of particles in the liquidfood composition of Example 3 as a distribution curve where verticalaxis is passing particle integrated value (%) based on volume.

FIG. 3( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Example 4 and FIG. 3( b) is afigure showing the particle size distribution of particles in the liquidfood composition of Example 4 as a distribution curve where verticalaxis is passing particle integrated value (%) based on volume.

FIG. 4( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Comparative Example 3 and FIG.4( b) is a figure showing the particle size distribution of particles inthe liquid food composition of Comparative Example 3 as a distributioncurve where vertical axis is passing particle integrated value (%) basedon volume.

FIG. 5( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Comparative Example 4 and FIG.5( b) is a figure showing the particle size distribution of particles inthe liquid food composition of Comparative Example 4 as a distributioncurve where vertical axis is passing particle integrated value (%) basedon volume.

FIG. 6( a) is a figure showing the particle size distribution ofparticles in a liquid food composition of Comparative Example 5 and FIG.6( b) is a figure showing the particle size distribution of particles inthe liquid food composition of Comparative Example 5 as a distributioncurve where vertical axis is passing particle integrated value (%) basedon volume.

FIG. 7 is a figure showing the time course of the amount of liquidpassing through a tube when each liquid food composition prepared inExamples 3 and 4 and Comparative Example 3 was subjected to passageperformance evaluation on tube feeding.

FIG. 8( a) is a figure showing the particle size distribution ofparticles in a liquid food composition A in a dependency evaluation onthe amount of an emulsifier added and FIG. 8( b) is a figure showing theparticle size distribution of particles in the liquid food composition Aas a distribution curve where vertical axis is passing particleintegrated value (%) based on volume.

FIG. 9( a) is a figure showing the particle size distribution ofparticles in a liquid food composition B in the dependency evaluation onthe amount of an emulsifier added and FIG. 9( b) is a figure showing theparticle size distribution of particles in the liquid food composition Bas a distribution curve where vertical axis is passing particleintegrated value (%) based on volume.

FIG. 10( a) is a figure showing the particle size distribution ofparticles in a liquid food composition C in the dependency evaluation onthe amount of an emulsifier added and FIG. 10( b) is a figure showingthe particle size distribution of particles in the liquid foodcomposition C as a distribution curve where vertical axis is passingparticle integrated value (%) based on volume.

FIG. 11( a) is a figure showing the particle size distribution ofparticles in a liquid food composition D in the dependency evaluation onthe amount of an emulsifier added and FIG. 11( b) is a figure showingthe particle size distribution of particles in the liquid foodcomposition D as a distribution curve where vertical axis is passingparticle integrated value (%) based on volume.

FIG. 12( a) is a figure showing the particle size distribution ofparticles in a liquid food composition E in the dependency evaluation onthe amount of an emulsifier added and FIG. 12( b) is a figure showingthe particle size distribution of particles in the liquid foodcomposition E as a distribution curve where vertical axis is passingparticle integrated value (%) based on volume.

FIG. 13 is a figure showing the generation state of aggregates as aresidue after the liquid food composition of Comparative Example 3 wasfiltered.

FIG. 14 is a figure showing the generation state of aggregates as aresidue after the liquid food composition of Comparative Example 4 wasfiltered.

FIG. 15 is a figure showing the generation state of aggregates as aresidue after the liquid food composition D was filtered in thedependency evaluation on the amount of an emulsifier added.

FIG. 16 is a figure showing the generation state of aggregates as aresidue after the liquid food composition E was filtered in thedependency evaluation on the amount of an emulsifier added.

FIG. 17( a) is a figure showing the particle size distribution ofparticles in a certain liquid food composition as a distribution curvewhere vertical axis is passing particle integrated value (%) based onvolume and FIG. 17( b) is a figure showing the relation that is preparedin order to determine an inflection point of the distribution curveshown in FIG. 17( a), that is between the particle size (nm) and thevariation (%) in the passing particle integrated value, and where thehorizontal axis is particle size (nm) and the vertical axis is thevariation (%) in passing particle integrated value.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail.

The liquid food composition of the present invention includes awater-soluble dietary fiber (a), a metal compound (b) containing anecessary mineral component for humans and not causing gelation of thewater-soluble dietary fiber in a neutral region, a protein (c), and anemulsifier (d) and is semi-solidified in an acidic region, and theliquid food composition is characterized by containing particles havinga particle size distribution with two or more peaks in a neutral region.

The “semi-solidification” in the present invention is a state in whichthe liquid nature of the liquid food composition is changed and meansinsolubilization, increase in viscosity, solation, gelation, and thelike of components in the composition. The state is not specificallylimited as long as the liquid nature at the time of intake is changed byan acidic condition in the stomach. The semi-solidification can also berepresented by the solidification ratio described later. In the presentinvention, the solidification ratio is not particularly limited but ispreferably 45% or more. A liquid food composition having asolidification ratio of 45% or more is more semi-solidified in an acidicregion in the stomach and consequently can more effectively provide, forexample, the prevention effect of gastroesophageal reflux disease,aspiration pneumonia, diarrheal disease, leakage from a fistula, and thelike, the relief of the feeling of hunger, and the suppression effect ofsudden increase in blood glucose level.

As the index for semi-solidification, viscosity can be also used. Theviscosity when the liquid food composition is semi-solidified is notparticularly limited as long as gastroesophageal reflux can be preventedand a feeling of satiety is enhanced, but the viscosity when the liquidfood composition is semi-solidified is preferably 1,000 cP or more, morepreferably 2,000 cP or more, even more preferably 5,000 cP or more, andspecifically preferably 10,000 cP or more. A semi-solidified liquid foodcomposition having a viscosity of 1,000 cP or more can more effectivelyprovide, for example, the prevention effect of gastroesophageal refluxdisease, aspiration pneumonia, diarrheal disease, leakage from afistula, and the like, the relief of the feeling of hunger, and thesuppression effect of sudden increase in blood glucose level.

In the present invention, the “liquid nature of a liquid foodcomposition” means a nature by which easiness in intake of the liquidfood composition is not impaired and means, for example, that there isno solid (for example, aggregate) causing tube clogging and thecomposition is in a uniform state. Here, the “uniform state” means thatcomponents are little separated and the product quality is good. Aliquid food composition in which components are largely separated haspoor appearance even when there is no solid (for example, aggregate)causing tube clogging. The poor appearance reduces the commercial valueand such a liquid food composition may not accepted in the market. Theliquid food composition of the present invention undergoes little changein physical properties such as solidification and separation ofcomponents even during storage for a long time and can sustain the“liquid nature” for a long time.

The water-soluble dietary fiber (a) usable in the present invention isnot particularly limited as long as the liquid nature of the liquid foodcomposition is not impaired at the time of intake and during storage andthe liquid food composition can be semi-solidified in an acidic region.Usable examples of the water-soluble dietary fiber (a) include alginicacid and/or a salt thereof, gellan gum, pectin, carrageenan, curdlan,and polyglutamic acid. Among them, alginic acid and/or a salt thereofare particularly preferably used.

The type of alginic acid and/or a salt thereof is not particularlylimited and products meeting standards for pharmaceutical excipients orstandards for food additives can be used. The type of a salt of alginicacid is not particularly limited but a sodium salt, a potassium salt,and an ammonium salt are especially preferred. From the viewpoint thatthe flowability in a neutral region is suppressed to low viscosity, thealginic acid and the salt thereof preferably has a viscosity of 500 cPor less, more preferably 300 cP or less, even more preferably 100 cP orless, and specifically preferably 50 cP or less, in a 1 wt % aqueoussolution (20° C.). In the present invention, the adequate concentrationof the water-soluble dietary fiber (a) such as alginic acid and/or asalt thereof (hereinafter, also collectively referred to as “alginicacid”) varies depending on a type of the water-soluble dietary fiber anda formulation of the composition, but from the viewpoint of furtheracceleration of the semi-solidification of the liquid food compositionin an acidic region, the concentration is principally 0.3 wt % or more,preferably 0.5 wt % or more, more preferably 0.7 wt % or more, and evenmore preferably 1.0 wt % or more, in the liquid food composition. Awater-soluble dietary fiber having a concentration of less than 0.3 wt %may lead to insufficient semi-solidification of the liquid foodcomposition in an acidic region. The upper limit of the concentration ofthe water-soluble dietary fiber such as alginic acid is preferably 5.0wt % or less, more preferably 2.5 wt % or less, even more preferably 2.0wt % or less, and most preferably 1.5 wt % or less, in the liquid foodcomposition. A water-soluble dietary fiber having a concentration ofmore than 5.0 wt % increases the viscosity of the liquid foodcomposition, and consequently the easiness in intake may be impaired.

The pH of the liquid food composition of the present invention is notparticularly limited as long as the liquid nature of the liquid foodcomposition is not impaired at the time of intake and during storage,but the liquid food composition principally preferably has a pH of morethan 5.5, more preferably a pH of 6.0 or more, and even more preferablya pH of 6.5 or more. A liquid food composition having a pH of 5.5 orless may lead to semi-solidification of the water-soluble dietary fiberin the composition and may not sustain the liquid nature at the time ofintake and during storage. The upper limit of pH of the liquid foodcomposition is also not particularly limited, but the liquid foodcomposition principally preferably has a pH of 10.0 or less, morepreferably a pH of 9.0 or less, and even more preferably a pH of 8.0 orless. A liquid food composition having a pH of more than 10.0 may leadto degradation of the water-soluble dietary fiber in the composition andmay result in insufficient semi-solidification of the liquid foodcomposition in an acidic region. The lower limit of the neutral regionin the present invention is preferably a pH of more than 5.5, morepreferably a pH of 6.0, and even more preferably a pH of 6.5. The upperlimit of the neutral region is preferably a pH of 10.0 or less, morepreferably a pH of 9.0 or less, and even more preferably a pH of 8.0.The acidic region in the present invention has a pH of 5.5 or less,preferably a pH of 4.5 or less, and more preferably a pH of 3.5 or less.

The term “not causing gelation of the water-soluble dietary fiber” inthe present invention means a compound that does not impair the liquidnature of the liquid composition even when the compound is mixed with awater-soluble dietary fiber (a) in a container and, for example, reactedwith the water-soluble dietary fiber (a). In other words, when theliquid nature of the composition is not impaired by mixing of a compoundthat has any characteristic or is in any state or in any amount, such acompound is regarded as a compound “not causing gelation of thewater-soluble dietary fiber”. Accordingly, in the present invention, themetal compound (b) not causing gelation of the water-soluble dietaryfiber in a neutral region is not limited to a metal compoundintrinsically having characteristics of not causing gelation of thewater-soluble dietary fiber in a neutral region. Even a metal compoundcausing gelation of the water-soluble dietary fiber in a neutral regioncan be used, if the compound is in any state that does not causegelation of the water-soluble dietary fiber in a neutral region or is inany amount that does not cause gelation of the water-soluble dietaryfiber in a neutral region.

The “necessary mineral component for humans” in the present inventionmeans essential minerals for humans, and examples of the mineralcomponent include sodium, potassium, calcium, magnesium, iron, zinc,copper, manganese, iodine, selenium, chromium, and molybdenum. Otherexamples include phosphorus, sulfur, and cobalt that are considered asessential minerals, and these minerals may be used in combination.However, it is preferably that such a compound has characteristics andused in a state or an amount that does not impair the liquid nature ofthe liquid food composition. Examples of the metal compound (b) that isusable in the present invention, contains a necessary mineral componentfor humans, and does not cause gelation of the water-soluble dietaryfiber in a neutral region include an alkali metal compound such as asodium compound and a potassium compound; an alkaline earth metalcompound such as a calcium compound and a magnesium compound; and othercompounds of a metal such as chromium, molybdenum, manganese, iron,copper, zinc, and selenium. These metal compounds may be in any state aslong as the gelation of the water-soluble dietary fiber is not causedwhen a food composition containing such a metal compound is in a neutralregion, but such a metal compound is preferably, for example, in thestate of a metal salt having poor solubility in a neutral region, in thestate contained in a microorganism such as a yeast, or in the statecontained in a microcapsule that has poor solubility in a neutral regionand is dissolved in an acidic region.

As the metal compound (b) not causing gelation of the water-solubledietary fiber in a neutral region, even a metal compound intrinsicallycausing gelation of the water-soluble dietary fiber due to itscharacteristics and state can be used as long as the liquid nature ofthe liquid food composition is not impaired at the time of intake andduring storage, for example, in an amount that is too small in theliquid food composition.

Among the metal compounds not causing gelation of the water-solubledietary fiber in a neutral region, a calcium compound and a magnesiumcompound are preferred because such compounds are a useful mineralcomponent. The calcium compound and the magnesium compound may have anystate as long as the gelation of the water-soluble dietary fiber is notcaused in a neutral region. Among them, a calcium compound having poorsolubility in a neutral region and a magnesium compound having poorsolubility in a neutral region are preferably used. Essential amounts ofcalcium and magnesium are higher than those of other mineral componentsin humans. Thus, the calcium compound having poor solubility and themagnesium compound having poor solubility are preferably used ratherthan the state contained in a yeast and the like.

A preferred calcium compound usable in the present invention is notparticularly limited as long as it has poor solubility in a neutralregion and has a solubility at which the liquid nature of the liquidfood composition is not impaired at the time of intake and duringstorage by the reaction with the water-soluble dietary fiber containedin the composition. For example, calcium citrate, calcium carbonate,calcium dihydrogen pyrophosphate, tricalcium phosphate, calciummonohydrogen phosphate, calcium stearate, and calcium silicate arepreferably used. Among them, calcium carbonate, calcium dihydrogenpyrophosphate, and tricalcium phosphate are preferably used. Among thesecalcium compounds, calcium carbonate and tricalcium phosphate are morepreferably used due to especially low solubility. These calciumcompounds may be used alone or in combination of two or more of them.

A preferred magnesium compound usable in the present invention is notalso particularly limited as long as it has poor solubility in a neutralregion and has a solubility at which the liquid nature of the liquidfood composition is not impaired at the time of intake and duringstorage by the reaction with the water-soluble dietary fiber containedin the composition. For example, magnesium carbonate, magnesium oxide,magnesium stearate, trimagnesium phosphate, and magnesium silicate arepreferably used. Among them, magnesium carbonate and magnesium oxidethat have poor solubility among magnesium compounds usable as foodadditives are more preferably used. These magnesium compounds may beused alone or in combination of two or more of them.

For the calcium compound and the magnesium compound, any of the abovecompounds may be used and the combination is not also particularlylimited, but as a combination that has suitable solubility in a neutralregion and that is suitably used for a food, a combination of calciumcarbonate and magnesium carbonate is especially preferred. Each amountin the food composition is not particularly limited as long as it is anutritionally satisfactory amount for a person taking the liquid foodcomposition and is a sufficient amount for the semi-solidification ofthe liquid food composition in an acidic region, but the amount ofcalcium is 0 μg/100 ml, 1 μg/100 ml or more, preferably 1 mg/100 ml ormore, more preferably 10 mg/100 ml or more, even more preferably 30mg/100 ml or more, furthermore preferably 50 mg/100 ml or more, andparticularly preferably 75 mg/100 ml or more, in terms of calcium. Theupper limit of the calcium amount is not particularly limited, but is3,000 mg/100 ml or less, preferably 2,000 mg/100 ml or less, morepreferably 1,000 mg/100 ml or less, even more preferably 500 mg/100 mlor less, and furthermore preferably 250 mg/100 ml or less. The amount ofmagnesium is 0 μg/100 ml, 1 μg/100 ml or more, preferably 1 mg/100 ml ormore, more preferably 10 mg/100 ml or more, even more preferably 15mg/100 ml or more, furthermore preferably 20 mg/100 ml or more, andparticularly preferably 35 mg/100 ml or more, in terms of magnesium. Theupper limit of the magnesium amount is not particularly limited, but is500 mg/100 ml or less, preferably 350 mg/100 ml or less, more preferably100 mg/100 ml or less, even more preferably 75 mg/100 ml or less, andfurthermore preferably 50 mg/100 ml or less.

The metal compound (b) may suitably include the calcium compound, themagnesium compound, and one or more compounds of the various metalcompounds described in the paragraph [0023] in a nutritionallysatisfactory amount for, for example, a person taking or administeringthe liquid food composition. The total amount of the metal compounds (b)is principally about 1 μg to 5 mg/100 ml, preferably about 1 μg to 50mg/100 ml, more preferably about 1 μg to 100 mg/100 ml, even morepreferably about 1 μg to 500 mg/100 ml, and furthermore preferably about1 μg to 1000 mg/100 ml.

The protein (c) used in the present invention is not particularlylimited, and usable examples of the protein include a plant protein suchas a soybean protein, a wheat protein, a pea protein, and a rice proteinand/or a hydrolysate of such a protein. However, a protein causinggelation of the dietary fiber in a neutral region is excluded. Amongthese proteins, a soybean protein and/or a hydrolysate thereof arepreferred. By mixing such a protein, the liquid nature of the liquidfood composition can be stably sustained during preparation and evenduring distribution and storage. The type of the soybean protein is notparticularly limited and usable examples of the soybean protein includea soy milk, a concentrated soybean protein, an isolated soybean protein,and a soybean peptide. The amount of the protein is not particularlydefined and is preferably a nutritionally satisfactory amount for aperson taking or administering the liquid food composition. The amountis 0.3 g/100 ml or more, more preferably 1.0 g/100 ml or more, even morepreferably 2.0 g/100 ml or more, and particularly preferably 4.0 g/100ml or more. The upper limit of the protein amount is principally 10.0g/100 ml or less, more preferably 7.5 g/100 ml or less, and particularlypreferably 5.0 g/100 ml or less because such a range is suitable forachieving the stability of the liquid food composition as the feature ofthe present invention. From the viewpoint of ensuring the flowability ina neutral region, a protein material preferably contains Ca in an amountof 2.0% or less, more preferably 1.5% or less, furthermore preferably1.0% or less, and particularly preferably 0.8% or less.

The emulsifier (d) usable in the present invention is not particularlylimited. From the viewpoint of suppressing the generation of aggregates,examples of the emulsifier include lysolecithin and a sucrose fatty acidester. As the lysolecithin, that derived from soybean or egg yolk can beused, and the lysolecithin derived from soybean is preferably used. Anyof a crude lysolecithin, a purified lysolecithin, a fractionatedlysolecithin, and an enzyme-modified lysolecithin may be used, and thepurified lysolecithin or the fractionated lysolecithin is preferablyused. The sucrose fatty acid ester is not particularly limited. Apreferred sucrose fatty acid ester includes, as a main component, amonoester composed of a fatty acid residue having a carbon number of 18or less, preferably 16 or less, more preferably 14 or less, and evenmore preferably 12 or less. Among them, a more preferred sucrose fattyacid ester includes, as a main component, a monoester with lauric acidspecifically having a carbon number of 12 or less. These emulsifiers maybe used alone and in combination of two or more of them.

The emulsifier (d) usable in the present invention can be selected withreference to HLB (hydrophile-lipophile balance) value of an emulsifier.From the viewpoint of suppressing the generation of aggregates, apreferably used emulsifier has an HLB value of more than 9, preferably10 or more, and more preferably 12 or more. Examples of the emulsifierhaving an HLB value of more than 9 include the lysolecithin (such asSLP-PasteLyso, SLP-WhiteLyso, and SLP-LPC70 manufactured by Tsuji OilMills Co., Ltd.) having an HLB value of about 12 and a sucrose fattyacid ester having an HLB value of more than 9, such as a sucrosestearate (S-970, S-1170, S-1570, and S-1670), a sucrose palmitate(P-1570 and P-1670), sucrose myristate (M-1695), sucrose oleate(O-1570), and a sucrose laurate (L-1695), manufactured byMitsubishi-Kagaku Foods Corporation. Among them, lysolecithin andsucrose laurate are preferably used.

The adequate concentration of the emulsifier (d) in the liquid foodcomposition varies depending on the formulation of the composition, butthe concentration in the liquid food composition is principallypreferably more than 0.17 wt % (when a fat is added, more than 5 wt %with respect to the fat), more preferably 0.24 wt % or more (when a fatis added, 7 wt % or more with respect to the fat), and even morepreferably 0.34 wt % or more (when a fat is added, 10 wt % or more withrespect to the fat). A liquid food composition containing the emulsifierin an amount of 0.17 wt % or less is unlikely to suppress the generationof aggregates. The upper limit is not particularly limited, but theaddition of the emulsifier in an excess amount leads to the increase inthe viscosity. Hence, the upper limit is 1.02 wt % or less (when a fatis added, 30 wt % or less with respect to the fat), preferably 0.85 wt %or less (when a fat is added, 25 wt % or less with respect to the fat),more preferably 0.68 wt % or less (when a fat is added, 20 wt % or lesswith respect to the fat), and even more preferably 0.51 wt % or less(when a fat is added, 15 wt % or less with respect to the fat).

The fat (e) usable in the present invention is not particularly limitedand usable examples of the fat include a natural fat such as a soybeanoil, a corn oil, a rape seed oil, a palm oil, a palm kernel oil, asafflower oil, an olive oil, a perilla oil, a fish oil, a beef tallow,and a lard; as well as a medium chain fatty acid triglyceride; asaturated fatty acid such as stearic acid; an unsaturated fatty acidsuch as oleic acid, α-linolenic acid, γ-linolenic acid, linoleic acid,eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid; and acombination of them. The amount of the fat (e) in the liquid foodcomposition is not particularly limited and the adequate amount variesdepending on the formulation of the composition, but the amount ispreferably a nutritionally satisfactory amount for a person taking oradministering the liquid food composition. Hence, the amount is about 0g/100 ml, preferably about 0.2 g/100 ml or more, more preferably about0.5 g/100 ml or more, even more preferably about 1.0 g/100 ml or more,furthermore preferably about 2.0 g/100 ml or more, particularlypreferably about 3.0 g/100 ml or more, and particularly more preferablyabout 3.4 g/100 ml or more. The upper limit of the amount of the fat isprincipally 10.0 g/100 ml or less, preferably 7.5 g/100 ml or less, morepreferably 5.0 g/100 ml or less, and particularly preferably 4.0 g/100ml or less because a formulation in such a range is preferred from theviewpoint of suppressing the generation of aggregates.

The amount of the emulsifier (d) can be controlled depending on theamount of a fat in the composition. The emulsifier (d) and the fat (e)are mixed in a ratio ((d)/(e), based on weight) of more than 5/100,preferably 7/100 or more, and more preferably 10/100 or more. Acomposition having a ratio of 5/100 or less is unlikely to suppress thegeneration of aggregates. The upper limit is not particularly limited,but in order not to increase the viscosity of the composition, the upperlimit is 30/100 or less, preferably 25/100 or less, more preferably20/100 or less, and furthermore preferably 15/100 or less.

In the present invention, a nutrient component (f) other than the abovecomponents may be included. In the present invention, a composition bywhich, for example, a person taking or administering the liquid foodcomposition can achieve intended nutritional support or nutritioncontrol is referred to as a “nutritionally satisfactory liquid foodcomposition”. The nutrient component capable of being included in theliquid food composition is not particularly limited as long as intendednutritional support or nutrition control can be achieved. As describedabove, in the present invention, the liquid food composition includesthe water-soluble dietary fiber (a), the metal compound (b) containing anecessary mineral component for humans, and the protein (c) as anitrogen source, such as a soybean protein and a hydrolysate thereof andresults in a nutritionally satisfactory liquid food composition. As themetal compound (b) containing a necessary mineral component for humans,a compound not causing gelation of the water-soluble dietary fiber (a)in a neutral region is preferably used. The use of a compound other thansuch a compound may cause a reaction with the water-soluble dietaryfiber in the composition, and consequently may impair the liquid natureof the liquid food composition during storage. As the protein as anitrogen source, an animal protein may be contained in addition to theplant protein such as a soybean protein and all nitrogen sources are notnecessarily derived from a plant protein such as a soybean protein. Forexample, a common protein such as a milk protein, sodium caseinate, andan egg protein as well as a peptide and hydrolysate derived from such aprotein may be properly used in combination as a nitrogen source.Furthermore, for the nitrogen source, for example, various amino acidssuch as an essential amino acid may also be used. However, such acompound is preferably used within characteristics, a state, and anamount not impairing the liquid nature of the liquid food composition.

For the nutrient component (f) other than the above components, anymaterial may be used as long as the liquid nature of the liquid foodcomposition is not impaired at the time of intake and during storage anda nutritionally satisfactory component for a person taking the liquidfood composition may be appropriately added. Examples of carbohydratesinclude starch, dextrin, and a hydrolysate of them; disaccharides suchas sucrose, maltose, and lactose; and monosaccharides such as glucoseand fructose, and these carbohydrates may be used in combination.Examples of vitamins include vitamins A group, B group, C, D, E, and K,folic acid, pantothenic acid, niacin, and biotin, and these vitamins maybe used in combination. Examples of minerals other than calcium andmagnesium include conventionally used various micronutrients and tracemetals such as sodium, potassium, calcium, magnesium, phosphorus, iron,zinc, copper, manganese, iodine, selenium, chromium, and molybdenum thatare minerals described in “Dietary Reference Intakes for Japanese(2010)”. Additional examples of the minerals include sulfur and cobaltthat are regarded as essential minerals, and these minerals may be usedin combination. The amount is not particularly limited as long as it isa nutritionally satisfactory amount for a person taking or administeringthe liquid food composition, but it is preferably that such a compoundhas characteristics, and used in a state, and an amount that does notimpair the liquid nature of the liquid food composition.

As the dietary fiber used in the present invention, usable examples ofwater-soluble dietary fibers include, in addition to the water-solubledietary fibers that semi-solidify the liquid food composition in anacidic region, agar, xanthan gum, locust bean gum, gum arabic, collagen,gelatin, fucoidan, glucomannan, polydextrose, starch, and inulin.Examples of insoluble dietary fibers include cellulose, crystallinecellulose, microcrystalline cellulose, hemicellulose, lignin, chitin,chitosan, a corn fiber, and a beet fiber. These dietary fibers may beused in combination.

The liquid food composition of the present invention may use a flavor, afruit juice, and a functional material. The constitution of nutrientcomponents in the liquid food composition of the present invention isnot particularly limited as long as intended nutritional support ornutrition control can be achieved and a person taking or administeringthe composition can be satisfied, but, for example, for the preparationof a typical enteral nutrition food, blending quantities are controlledso that the protein content will be 0.5 to 10 wt %, the fat content willbe 1 to 10 wt %, and the carbohydrate content will be 5 to 40 wt %.

A so-called “liquid diet” may be used as the nutrient component andcommercially available products such as Ensure Liquid (registeredtrademark) from ABBOTT JAPAN Co., Ltd. and MA-7 from Morinaga MilkIndustry Co., Ltd. (distributor: Clinico Co., Ltd.) may be used.

In the present invention, the particle size distribution of particlescontained in the liquid food composition includes two or more peaks in aneutral region.

Focusing on the particle size distribution of particles contained in theliquid food composition as above, it has been found that, in particular,a composition of which particle size distribution includes two or morepeaks is likely to suppress the generation of aggregates.

In the present invention, “particles” mean substances being dispersedand/or suspended in a liquid as a continuous phase in the liquid foodcomposition. The “particles” may be composed of any component as long asthey are substances being dispersed and/or suspended in a liquid but theparticles are supposed to be composed of independently and/or incombination of the following components; a water-soluble dietary fiber,a metal compound, a protein, an emulsifier, a fat, a nutrient component(such as a carbohydrate and a dietary fiber), and the like.

The particle size distribution of particles in the liquid foodcomposition can be determined and evaluated by using, for example, aparticle size distribution analyzer employing laserdiffraction/scattering method.

Hereinafter, an example of the determination method of particle sizedistribution will be described using a laser diffraction/scatteringparticle size distribution analyzer (LA-950 manufactured by Horiba,Ltd.) as the particle size distribution analyzer.

Analysis conditions of the laser diffraction/scattering particle sizedistribution analyzer are as follows; dispersion medium: distilledwater; sample refractive index: 1.600 to 0.000 i; dispersion mediumrefractive index: 1.333; circulation rate: 13; and stirring rate: 2. Forthe analysis, a sample concentration is adjusted so that a lighttransmission factor (R) is set to 90 to 80% and a transmittance (B) to90 to 70%. When a liquid food composition is subjected to ultrasonictreatment, the composition is sonicated at an ultrasonic treatmentintensity of 3 for 3 minutes, and then the particle size distribution ofparticles is analyzed in the above analysis conditions for ascertainingthe change in the particle size distribution of particles contained inthe liquid food composition before and after the ultrasonic treatment.

When the particle size distribution is analyzed in the conditions, theparticle size distribution of particles is represented by a distributioncurve where the horizontal axis is particle size (nm) and the verticalaxis is frequency (%) based on volume in the analysis by the laserdiffraction/scattering method. A peak in a particle size distribution inthe present invention is a point showing a maximum frequency value in atriangular distribution curve having a base on the horizontal axis(particle size). The starting point and/or the end point of thetriangular distribution curve are not necessarily in contact with thehorizontal axis (particle size), and a distribution curve of whichstarting point and/or end point have a frequency (%) of between 0 to 5%can be considered as the triangular distribution.

When a liquid food composition of which pH is in a neutral region hastwo or more peaks in the particle size distribution of particles whichis determined by the method exemplified in the above, such a liquid foodcomposition is regarded as the liquid food composition of the presentinvention. From the viewpoint of suppressing the generation ofaggregates, at least one peak of two or more peaks present in theparticle size distribution of particles has a particle size of 3,000 nmor smaller, more preferably a particle size of 2,000 nm or smaller, andeven more preferably a particle size of 1,000 nm or smaller.

It is more preferred that ultrasonic treatment of a liquid foodcomposition having a peak of the particle size distribution in such aspecific particle size section increases the frequency of the at leastone peak having a particle size of 3,000 nm or smaller, more preferably2,000 nm, and even more preferably a particle size of 1,000 nm orsmaller, after the ultrasonic treatment as compared with that before theultrasonic treatment, and reduces the frequency of at least one peakother than the peak having the increased frequency after the ultrasonictreatment as compared with that before the ultrasonic treatment.

Here, the increase and decrease of a peak frequency before and after theultrasonic treatment of the liquid food composition can be evaluated bythe equation.

(Peak frequency after ultrasonic treatment)/(peak frequency beforeultrasonic treatment)×100

Evaluating the peak having the increased frequency after the ultrasonictreatment in accordance with the above equation, the increased peakfrequency is 105% or more, preferably 110% or more, even more preferably120% or more, and furthermore preferably 130% or more with respect tothe frequency in the particle size distribution of particles before theultrasonic treatment. The peak having the reduced frequency after theultrasonic treatment with the frequency in the particle sizedistribution of particles before the ultrasonic treatment, has thereduced peak frequency of 60% or less, preferably 50% or less, morepreferably 40% or less, and furthermore preferably 30% or less withrespect to the frequency in the particle size distribution of particlesbefore the ultrasonic treatment.

When the particle size distribution is determined in the conditions, theparticle size distribution of particles is also represented by adistribution curve where the horizontal axis is particle size (nm) andthe vertical axis is passing particle integrated value (%) based onvolume in the analysis by the laser diffraction/scattering method. Aninflection point in the particle size distribution in the presentinvention is a point where a curvature sign in the distribution curve ischanged and a tangential line at the point intersects with thedistribution curve itself.

The liquid food composition of the present invention has two or moreinflection points and more preferably three or more inflection points inthe particle size distribution curve of particles when the particle sizedistribution of particles in the liquid food composition of which pH isin a neutral region is determined by the method exemplified in theabove. From the viewpoint of suppressing the generation of aggregates,it is preferred that at least one point of two or more inflection pointspresent in the particle size distribution curve of particles is presentin a particle size section having a particle size of 3,000 nm orsmaller, more preferably a particle size of 2,000 nm or smaller, andeven more preferably a particle size of 1,500 nm or smaller.

It is preferred that, in the liquid food composition of the presentinvention, at least one of the inflection points present in the particlesize distribution curve of particles is present in a particle sectionhaving a particle size of 2,000 nm or smaller, and ultrasonic treatmentof the liquid food composition increases a passing particle integratedvalue (%) corresponding to the at least one inflection point by 5% ormore, preferably 10% or more, even more preferably 15% or more, andparticularly preferably 20% or more after the ultrasonic treatment ascompared with that before the ultrasonic treatment. It is more preferredthat the passing particle integrated value (%) corresponding to at leastone of the inflection points, the at least one inflection point beingpresent in a particle section having a particle size of 2,000 nm orsmaller, is present in a passing particle integrated value section of25% or more, preferably 35% or more, even more preferably 50% or more,and particularly preferably 75% or more, after the ultrasonic treatment.

The inflection point can be (simply) determined, for example, by thefollowing manner. That is, from passing particle integrated values (%)at an arbitrary particle size (x) nm and a particle size (x+1) nm, thevariation in passing particle integrated value (=[integrated value (%)of particle size (x+1)]−[integrated value (%) of particle size (x)]) iscalculated. From the variation in passing particle integrated value ineach particle size section, the change of curvature of a distributioncurve can be ascertained, and a boundary point (a point at which thecurvature sign is changed) between a particle size section where thevariation in passing particle integrated value increases (the curvaturesign is “+”) and a particle size section where the variation in passingparticle integrated value decreases (the curvature sign is “−”) isregarded as the inflection point.

As an example, the particle size distribution of particles in a liquidfood composition will be described with reference to FIG. 17( a) andFIG. 17( b). FIG. 17( a) shows the particle size distribution as adistribution curve where the vertical axis is passing particleintegrated value (%) based on volume. In FIG. 17( b), the horizontalaxis is particle size (nm) and the vertical axis is variation in thepassing particle integrated value (%). As shown in FIG. 17( b), in thesection having a particle size from about 10 nm and about 3,400 nm orsmaller and the section having a particle size of about 30,000 nm orlarger, the curvature of the distribution curve has no variation (bothvariations are 0% in FIG. 17( b)). In the section having a particle sizeof about 3,400 nm or larger and a particle size of about 10,000 nm orsmaller, the curvature of the distribution curve is changed as positive(+) (in FIG. 17( b), the variation increases with the increase of theparticle size). In the section having a particle size of about 10,000 nmor larger and about 30,000 nm or smaller, the curvature of thedistribution curve is changed as negative (−) (in FIG. 17 (b), thevariation decreases with the increase of the particle size). Asdescribed above, there is the point where the curvature of thedistribution curve is changed at the particle size of around 10,000 nm(in FIG. 17( b), near the peak), and the point is regarded as theinflection point. In other words, in this example, in the distributioncurve of the particle size distribution (FIG. 17( a)) where thehorizontal axis is particle size (nm) and the vertical axis is passingparticle integrated value (%), it is revealed that the inflection pointis present at a particle size of around 10,000 nm and a passing particleintegrated value of around 47%.

In the present invention, the liquid food composition preferably has anaggregate weight determined by the measurement method below of 0.1 g orless. A liquid food composition having an aggregate weight of more than0.1 g is likely to cause clogging in a tube at the time of tube feedingor cause granular texture and the like at the time of oral intake. Fromthe viewpoint of the granular texture and swallowing feeling at the timeof oral intake, the aggregate weight is more preferably 0.07 g or less,more preferably 0.05 g or less, even more preferably 0.03 g or less, andmost preferably 0.01 g or less. A liquid food composition having such anaggregate weight is likely to be judged as less or no granular texture.

Here, the “aggregate” is a substance that is formed during preparationor storage of the liquid food composition and that may cause clogging ina tube at the time of tube feeding or may cause granular texture and thelike at the time of oral intake of the liquid food composition. Theaggregate is supposed to be composed of particles in the liquid foodcomposition, aggregated particles, a water-soluble dietary fiber, ametal compound, a protein, an emulsifier, a fat, a nutrient component(such as a carbohydrate and a dietary fiber), and the like that areindependent of and/or in combination with one another.

The formation amount of the aggregate that may cause the tube cloggingor the granular texture can be evaluated by, for example, the weight ofa residue after the filtration of the liquid food composition through anylon screen, a filter paper, or the like.

Hereinafter, a specific example of the measurement method of aggregatesin the liquid food composition will be described.

(i) The dry weight (regarded as W1) of a nylon screen (HC-58(manufactured by NYTAL), mesh: 264 inch) is weighed.

(ii) The nylon screen is placed on a Buchner funnel (pore size: 2 mm)having a diameter of 11 cm, and the Buchner funnel is set to a suctionbottle.

(iii) Using ASPIRATOR A-3S (manufactured by EYELA), 200 ml of a liquidfood composition is filtered while decompressing the suction bottle.

(iv) The nylon screen after the filtration is dried at 60° C. for 1 hourand cooled to room temperature and then the dry weight (regarded as W2)is weighed.

(v) From the dry weight difference (W2−W1) before and after thefiltration, the weight of aggregates obtained as the residue iscalculated.

In the present invention, as mentioned above, focusing on the particlesize distribution of particles contained in the liquid food composition,it has been found that, in particular, a composition of which particlesize distribution includes two or more peaks is likely to suppress thegeneration of aggregates. It has also been found that a preferredcomposition has two peaks which undergo certain changes by ultrasonictreatment as above.

While not wishing to be bound by theory, the present inventors supposethe relation between the generation of aggregates and the particle sizedistribution and/or the change in particle size distribution as follows.It is known that a water-soluble dietary fiber such as alginic acid andpectin generally has poor compatibility with particles (emulsion (anemulsifier or a fat) and with a biopolymer (for example, a protein) inthe composition and thus induces the “aggregation” of particles due tovarious actions such as depletion interaction, electrostaticinteraction, and intermolecular cross-linking action. It is believedthat particles in a composition are “flocculated” in a step before thestep of causing the “aggregation” and then the “flocculated” particlesare bonded to generate the “aggregates”. In other words, the particlesin a “flocculated” state are independent of each other and hence theparticles are easily re-dispersed, while the particles in an“aggregated” state are bonded to each other and hence the particles areno longer re-dispersed. In addition, it is supposed that the particlesin an “aggregated” state are “flocculated” with each other, and thenfurther aggregated to form larger aggregates.

In the present invention, it is supposed that the composition of whichparticle size distribution of particles (horizontal axis: particle size(nm), vertical axis: volumetric frequency (%)) has two or more peaksand/or the composition of which particle size distribution of particlesis changed by ultrasonic treatment are a result of observing theparticles in the “flocculated” state. In other words, it is supposedthat the (at least one) peak observed at a particle size of 3,000 nm orsmaller in the particle size distribution of particles shows theoriginal particle size of particles, while another peak (observed at aparticle size of 1,000 nm or larger) shows the particles in the“flocculated” state. In addition, it is supposed that the increase inthe frequency of the (at least one) peak observed at a particle size of3,000 nm or smaller by ultrasonic treatment of the composition and thereduction in the frequency of the (at least one) peak other than thepeak having the increased frequency shows the phenomenon ofre-dispersion of the particles in the flocculated state, which can beexplained by the suggestion above. In contrast, a single peak observedin the particle size distribution of a conventional liquid foodcomposition is supposed to be a result of observing the particles in the“aggregated” state above, and it is supposed that such particles areno-longer re-dispersed to readily generate aggregates. As describedabove, by the evaluation of particles present in the composition whiledistinguishing between the “flocculation” and the “aggregation”, thegeneration of aggregates during preparation and/or during storage of thecomposition can be appropriately evaluated for the first time. Such anevaluation can lead to the suppression of the aggregate generationduring preparation and/or during storage of the composition.Consequently, the liquid food composition that is unlikely to causeclogging in a tube and has good tube passage performance at the time oftube feeding, has less “granular texture” and good “swallowing feeling”at the time of oral intake, and is consequently easy to be taken can beprovided.

The method for producing the liquid food composition of the presentinvention is not particularly limited but the liquid food compositioncan be prepared in usual ways. For example, to water, a water-solubledietary fiber (a), a metal compound (b) containing a necessary mineralcomponent for humans and not causing gelation of the water-solubledietary fiber (a) in a neutral region, a protein (c), an emulsifier (d),as well as a fat (e), and other nutrient components (f) such as aprotein, a carbohydrate, vitamins and minerals are appropriately added;the whole is mixed; and the mixture is homogenized with a high-pressureemulsification equipment, a homogenizer, or the like. The preparedliquid food composition may be filled in a pouch such as a soft bag andan aluminum pouch and a container such as a paper package, a can, and abottle; and subjected to common sterilization treatment such as heat andpressure sterilization using a retort, an autoclave, or the like,energized thermal sterilization, and microwave heat sterilization. Sucha sterilization treatment can suppress the alteration of physicalproperties of the liquid food composition due to microorganisms and thelike. The sterilization treatment may also be carried out after thefilling of the liquid food composition in a container, but any methodmay be employed as long as the alteration of physical properties of theliquid food composition due to microorganisms and the like can besuppressed.

The container filled with the liquid food composition may be composed ofany material and may have any form, but the container used in thepresent invention preferably has a form by which physical properties ofthe liquid food composition are not altered due to the contamination ofmicroorganisms and the like. Furthermore, from the viewpoint ofsuppressing the reduction of nutrient components such as vitamins, thecontainer is preferably made from a material having light blockingproperties and/or gas barrier properties, but the container may betransparent. The liquid food composition of the present invention doesnot impair the liquid nature of the composition even when awater-soluble dietary fiber is preliminarily added and hence thewater-soluble dietary fiber (a) and other all components such as a metalcompound (b), a protein (c), and an emulsifier (d) can be filled in acontainer. In the present invention, the state filling a liquid foodcomposition in a container as above is referred to as a “one-pack typeproduct”. In contrast, as related arts disclosed in Patent Documents 1and 2, a product including a liquid food and a gelling agent such as awater-soluble dietary fiber that are separately packed is referred to asa “two-pack type product”. In addition, a product including a liquidfood and a gelling agent such as a water-soluble dietary fiber in acontainer of which inside is separated by a partition wall or the likeso that the liquid food and the gelling agent are not mixed is alsoreferred to as a “two-pack type product”.

The liquid food composition of the present invention prepared as aboveis a one-pack type product to which a water-soluble dietary fiber ispreliminarily added, but undergoes little change in physical propertiessuch as solidification and separation of components during productionprocess and distribution as well as even during storage, andconsequently can stably sustain the quality for a long time. As aresult, a liquid food composition having an advantage that thecomposition is liquid before entering the stomach and is thickenedand/or semi-solidified in the stomach can be practically supplied to themarket. In addition, the liquid food composition that is unlikely tocause clogging in a tube and has good tube passage performance at thetime of tube feeding, has less “granular texture” and good “swallowingfeeling” at the time of oral intake, and is consequently easy to betaken can be provided because the generation of aggregates can besuppressed during preparation and/or during storage of the composition.

The liquid food composition of the present invention can employ acommonly used distribution condition and storage condition and can bedistributed and stored in a temperature condition of 0° C. to 40° C.However, the distribution and storage are preferably at 4° C. to 30° C.and more preferably at 4° C. to 25° C. Distribution and/or storage in acondition of less than 0° C. may lead to the freeze of water in theliquid food composition to separate food components, while distributionand/or storage in a condition of more than 40° C. may lead to thereduction of nutrient components such as vitamins in the liquid foodcomposition. The liquid food composition of the present invention can bedistributed and stored either in a bright place or in a dark place, butfrom the viewpoint of suppressing the reduction of nutrient componentssuch as vitamins, the liquid food composition is preferably distributedand stored in a dark place.

The liquid food composition of the present invention can be taken by aconventional method such as oral intake and tube feeding. For example,the liquid food composition can be taken directly from a mouth and canbe taken dropwise through a tube from a container hung on a stand. Theliquid food composition can be forcibly taken, for example, using a pumpor a pressure bag or by pressurizing a container by hand, but the intakemethod is not limited to them. The viscosity of the liquid foodcomposition is not particularly limited as long as the easiness inintake is not impaired by each intake method, but the viscosity is lessthan 1,000 cP, preferably 500 cP or less, more preferably 400 cP orless, even more preferably 300 cP or less, and furthermore preferably200 cP or less. A liquid food composition having a viscosity of 1,000 cPor more may be difficult to pass through a tube or the like to impairthe easiness in intake. When the liquid food composition is orallytaken, from the viewpoint of granular texture and swallowing feeling, acomposition having a viscosity of 170 cP or less gives thickness feelingbut easily taken. For swallowing feeling and easy intake, thecomposition has a viscosity of 150 cP or less, preferably 135 cP orless, more preferably 100 cP or less, even more preferably 85 cP orless, and most preferably 80 cP or less.

The liquid food composition of the present invention is semi-solidifiedin an acidic region in the stomach. Accordingly, the liquid foodcomposition is expected to have, for example, the prevention effect ofgastroesophageal reflux disease, aspiration pneumonia, diarrhealdisease, leakage from a fistula, and the like and the effects on reliefof the feeling of hunger and on suppression of sudden increase in bloodglucose level. The pH at the time of the semi-solidification is notparticularly limited, but from the viewpoint of good semi-solidificationin an acidic environment in the stomach, a composition that issemi-solidified at a pH of 5.5 or less is preferred, that issemi-solidified at a pH of 5.0 or less is more preferred, that issemi-solidified at a pH of 4.8 or less is even more preferred, and thatis semi-solidified at a pH of 4.5 or less is particularly preferred.

Using the above advantages, the liquid food composition of the presentinvention can be used for a nutrition food, an enteral nutrition food,an enteral nutrient including a diet classified as a medicinal supplies,an elemental diet, a polymeric formula, an oligomeric formula, a highdensity liquid diet, a diet food, a food for diabetes, and the like. Asdescribed above, the liquid food composition of the present inventioncan be taken by a method such as oral intake and tube feeding. Theintake method is not particularly limited but the liquid foodcomposition is suitable as an enteral nutrition food or an enteralnutritional supplement that is taken through a tube such as anasogastric tube or a tube from a gastrostomy.

EXAMPLES

Hereinafter, examples and comparative examples will be described inorder to specifically explain the present invention, but the presentinvention is not limited to them.

For the evaluation of physical properties representing the feature ofthe present invention, the following examinations were carried out.

<Determination of Viscosity of Liquid Food Composition>

The viscosity of a liquid food composition was determined with a“Brookfield viscometer (manufactured by Tokimec, Inc.)”. Specifically, asample for measurement was charged into a glass container having aninner diameter of 60 mm, then the viscosity was measured three times ina condition at a liquid temperature of 25° C. using a No. 2 rotor at arotation speed of 60 revolutions per minute and a holding time of 30seconds, and the mean value was calculated as a measured value(viscosity).

<Ascertainment of Semi-Solidification of Liquid Food Composition inAcidic Region and Calculation of Solidification Ratio>

The ascertainment of semi-solidification of a liquid food composition inan acidic region was carried out in the following manner. Asolidification ratio was calculated in Examples 3 and 4, ComparativeExamples 3 to 5, and the dependency evaluation on the amount of anemulsifier added described later.

(1) Into a 50-ml plastic tube, 20 g of artificial gastric juice (theJapanese Pharmacopoeia) kept at 37° C. is charged.

(2) Into the artificial gastric juice, 10 g of a liquid food compositionstored at 25° C. is charged, the plastic tube containing the artificialgastric juice and the liquid food composition is weighed (regarded as[tube weight before filtration]).

(3) The plastic tube is gently stirred with a “HL-2000 HybriLinker(manufactured by UVP Laboratory Products)”. Specifically, the tube isfixed to a fixture in a chamber, a motor control knob of the apparatusis set at “MIN”, and the tube is stirred in a condition at 37° C. for 2minutes 30 seconds.

(4) A solid is collected on a nylon screen (40 mesh; manufactured bySogo Laboratory Glass Works Co., Ltd.) by filtration under vacuum toremove a liquid portion; then the solid with the nylon screen is placedon a paper towel or the like and excess water is removed for 2 minutes;the solid with the nylon screen is weighed (regarded as [solid weightafter filtration]); and the plastic tube after washing the contentliquid is weighed ([tare weight after filtration]).

(5) The solid residue on the nylon screen is ascertained. Thesolidification ratio is calculated in accordance with Equation (1).

$\begin{matrix}{\left\lbrack {{Mathematical}\mspace{14mu} {Formula}\mspace{14mu} 1} \right\rbrack } & \; \\{{{Solidification}\mspace{14mu} {ratio}\mspace{14mu} (\%)} = \frac{\begin{matrix}{\left\lbrack {{Solid}\mspace{14mu} {weight}\mspace{20mu} {after}\mspace{14mu} {filtration}} \right\rbrack -} \\\left\lbrack {{Nylon}\mspace{14mu} {screen}\mspace{14mu} {weight}} \right\rbrack\end{matrix}}{\begin{matrix}\begin{matrix}{\left\lbrack {{Tube}\mspace{14mu} {weight}\mspace{14mu} {before}\mspace{14mu} {filtration}} \right\rbrack -} \\{\left\lbrack {{Tare}\mspace{14mu} {weight}\mspace{14mu} {after}\mspace{14mu} {filtration}} \right\rbrack -}\end{matrix} \\\left\lbrack {{Artificial}\mspace{20mu} {gastric}\mspace{14mu} {juice}\mspace{14mu} {weight}} \right\rbrack\end{matrix}}} & {{Equation}\mspace{14mu} (1)}\end{matrix}$

<Determination of Particle Size Distribution of Liquid Food Composition>

In Examples 1, 3, and 4, Comparative Examples 3 to 5, and the dependencyevaluation on the amount of an emulsifier added, in accordance with themethod described above using a laser diffraction/scattering particlesize distribution analyzer (LA-950 manufactured by Horiba, Ltd.) as aparticle size distribution analyzer, the particle size distribution ofaggregates in a liquid food composition was determined.

<Weighing of Aggregate in Liquid Food Composition>

In accordance with the above weighing method of aggregates in a liquidfood composition using a nylon screen, the weight of aggregates wascalculated from the dry weight difference before and after filtration.

<Evaluation by Oral Intake>

In Examples 1, 3, and 4, Comparative Examples 3 to 5, and the dependencyevaluation on the amount of an emulsifier added described later, theliquid food composition was evaluated in oral intake. The evaluation wascarried out by the presence or absence of granular texture andswallowing feeling as indices. For the granular texture evaluation, acomposition having the granular texture at the time of oral intake isevaluated as “presence”, while a composition without the granulartexture is evaluated as “absence”. For the swallowing feelingevaluation, a composition capable of being taken with good swallowingfeeling is evaluated as “A”, a composition that has thickness feelingbut is readily taken is evaluated as “B”, and a composition that haspoor flowability and is difficult to be taken is evaluated as “C”.

Reference Example 1

To 400 ml distilled water, 2.5 g of sodium alginate (KIMICAALGIN IL-2:manufactured by KIMICA corporation) was added to prepare 0.5 wt %aqueous sodium alginate solution. Next, 1.15 g of calcium carbonate and0.75 g of magnesium carbonate were mixed to the aqueous sodium alginatesolution. The mixture was cooled to room temperature, and then addedwith distilled water to make the volume 500 ml. A soft bag (R1420H:manufactured by Meiwa Pax Co., Ltd.) was filled with 200 g of theprepared liquid food composition, and the whole was sterilized (121° C.,20 minutes) in an autoclave sterilizer.

The prepared product was liquid and had a pH of 9.9 and a viscosity of10 cP. Ascertaining the semi-solidification in an acidic condition, theprepared product was semi-solidified in an artificial gastric juice andgave a solid residue on a nylon screen. Even after standing storage (25°C.) for a month, the prepared product was not changed in the pH andviscosity and also in the degree of semi-solidification in the acidiccondition.

In this manner, it was ascertained that the liquid food compositioncontaining sodium alginate, the calcium compound having poor solubilityin a neutral region, and the magnesium compound having poor solubilityin a neutral region as basic components did not undergo the change inthe liquid nature during preparation and even after storage and wassemi-solidified in an acidic condition. In addition, the preparedproduct was a liquid food composition capable of satisfying nutritionalrequirements because the magnesium compound was added.

Example 1

Based on the formulation described in Table 1, a liquid food compositioncontaining 0.5 wt % sodium alginate was prepared.

TABLE 1 Amount Added Comparative Comparative Component Example 1 Example1 Example 2 Sodium alginate 0.5 g 0.5 g 0.5 g Dextrin 12.2 g 12.2 g 12.2g Soybean protein 4.3 g 4.3 g — Sodium caseinate — — 4.3 g Fat(including emulsifier) 3.4 g 3.4 g 3.4 g Calcium carbonate 230 mg — 230mg Calcium dihydrogen phosphate — 580 mg — Magnesium carbonate 150 mg —150 mg Magnesium sulfate — 420 mg — Other minerals 1330 mg 1330 mg 1330mg Vitamins 62 mg 62 mg 62 mg Distilled water Balance Balance BalanceTotal 100 ml 100 ml 100 ml pH   6.7 —   6.8 Viscosity 110 — 110Generation frequency of solid None Gelated None Occurrence degree ofcomponent A /**⁾ B separation *⁾ *⁾ A: Component separation was notoccurred B: Component separation was occurred **⁾Evaluation wasimpossible due to gelation

To 650 ml of distilled water, 5 g of sodium alginate was added. Next, adextrin powder and a soybean protein powder (manufactured by Fuji OilCo., Ltd.) were added. A fat (containing an emulsifier) was furtheradded, then calcium carbonate, magnesium carbonate, other minerals, andvitamins were sequentially added, and the whole was stirred. The otherminerals used were a mixture of a zinc-containing yeast, acopper-containing yeast, a manganese-containing yeast, achromium-containing yeast, a selenium-containing yeast, amolybdenum-containing yeast (these mineral-containing yeasts:manufactured by Medience Corporation), and ferric sodium citrate(manufactured by Ebisu Co., Ltd.). Then, distilled water was added tomake the volume 1,000 ml and the mixture was homogenized with a MantonGaulin high-pressure emulsification equipment (Rannie 2000: manufacturedby APV) (for the first time: 20 MPa, for the second time: 48 MPa). Eachsoft bag (R1420H: manufactured by Meiwa Pax Co., Ltd.) was filled with200 g of the prepared liquid food composition containing 0.5 wt % sodiumalginate, and the whole was sterilized (121° C., 20 minutes) in anautoclave sterilizer.

The liquid food composition was a uniform liquid and the generation ofsolids and the separation of nutrient components were not observed. Theliquid food composition had a pH of 6.7 and a viscosity of 110 cP andshowed flowability. Ascertaining the semi-solidification in an acidiccondition, the liquid food composition was semi-solidified in anartificial gastric juice and gave a solid residue on a nylon screen. ThepH, the viscosity, the generation degree of solids, and the occurrencedegree of component separation of the liquid food composition are shownin Table 1.

Even after standing storage (25° C.) for three months, the liquid foodcomposition was not changed in the pH and viscosity and was littlechanged during storage in physical properties, for example, componentseparation. The degree of semi-solidification in the acidic conditionwas also not changed.

In this manner, it was ascertained that the liquid food compositioncontaining sodium alginate, the calcium compound having poor solubilityin a neutral region, the magnesium compound having poor solubility in aneutral region, the metal compounds of zinc, copper, manganese,chromium, selenium, and molybdenum included in yeasts, the iron compoundin a small amount not causing gelation of sodium alginate, and thesoybean protein as basic components sustained the liquid nature duringpreparation and even after storage, underwent little change in physicalproperties, for example, little component separation, and wassemi-solidified in an acidic condition. In addition, it was a liquidfood composition capable of satisfying nutritional requirements becausethe mineral components necessary for humans and the protein were added.

Analyzing the particle size distribution of particles in the liquid foodcomposition (Example 1), as shown in FIG. 1( a), the particle sizedistribution had two peaks and the smaller peak was present in a sectionhaving a particle size of 3,000 nm or smaller (at a particle size of 259nm and a frequency of 6.940%). The ultrasonic treatment reduced thefrequency of the larger peak and increased the frequency of the smallerpeak present in the section having a particle size of 3,000 nm orsmaller. Evaluating each peak frequency increased or reduced before andafter the ultrasonic treatment by the aforementioned equation (peakfrequency after ultrasonic treatment)/(peak frequency before ultrasonictreatment)×100), the smaller peak having the increased peak frequencywas 154% (=10.700%/6.940%×100), while the larger peak having the reducedpeak frequency was 47% (=2.548%15.401%×100).

As shown in FIG. 1( b), representing the particle size distribution ofthe liquid food composition (Example 1) as a distribution curve wherethe vertical axis is passing particle integrated value (%) based onvolume, the particle size distribution curve had three inflection pointsof (1) at a passing particle integrated value of around 20.23% and aparticle size of around 226 nm, of (2) at around 39.75% and around 669nm, and of (3) at around 74.55% and around 5,133 nm. The passingparticle integrated value of the inflection point (2) increased by 21%after the ultrasonic treatment as compared with that before theultrasonic treatment, and the inflection point (2′) after the ultrasonictreatment was at around 60.86% and around 669 nm.

The liquid food composition had less granular texture and goodswallowing feeling at the time of oral intake and was readily taken.

Comparative Example 1

Based on the formulation described in Table 1, a liquid food compositioncontaining 0.5 wt % sodium alginate was prepared in a similar manner tothat in Example 1.

The calcium compound used was “calcium dihydrogen phosphate monohydrate”and the magnesium compound used was “magnesium sulfate heptahydrate”.These compounds are metal salts soluble in a neutral region.

In the liquid food composition, the generation of solids was observedduring the production process and the whole turned into a gel after thesterilization treatment.

This is supposed to be because although the Ca amount and the Mg amountwere the same but the soluble calcium compound and the soluble magnesiumcompound were used and divalent ions of calcium ions and magnesium ionsderived from the compounds caused the gelation of sodium alginate.

In this manner, when the soluble calcium compound and the solublemagnesium compound were used, the intended liquid food composition ofthe present invention could not be prepared.

Comparative Example 2

Based on the formulation described in Table 1, a liquid food compositioncontaining 0.5 wt % sodium alginate was prepared in a similar manner tothat in Example 1.

The protein source used was sodium caseinate in place of the soybeanprotein.

The obtained food composition was liquid and had a pH of 6.8 and aviscosity before semi-solidification of 110 cP. Ascertaining thesemi-solidification in an acidic condition, the liquid food compositionwas semi-solidified in an artificial gastric juice to give a solidresidue on a nylon screen. However, after the sterilization treatment ofthe liquid food composition, the components were separated into twolayers. The pH, the viscosity, the generation degree of solids, and theoccurrence degree of component separation of the liquid food compositionare shown in Table 1.

In this manner, when sodium caseinate as a milk protein was used inplace of the soybean protein as a plant protein, the food compositiondid not entirely turn into a gel but caused component separation and theintended liquid food composition of the present invention could not beprepared.

Example 2

In a similar manner to that in Example 1, liquid food compositions (1)without sodium alginate, (2) containing 0.3 wt % sodium alginate, (3)containing 0.5 wt % sodium alginate, (4) containing 1.0 wt % sodiumalginate, and (5) containing 1.5 wt % sodium alginate were prepared. Thesodium alginates used were “KIMICAALGIN IL-2: manufactured by KIMICAcorporation” in (2) to (4) and “KIMICAALGIN IL-1: manufactured by KIMICAcorporation” in (5), while the protein source used was a soybeanprotein.

TABLE 2 (1) (2) (3) (4) (5) Concentration of sodium alginate Without 0.3wt 0.5 wt 1.0 wt 1.5 wt addition % IL2 % IL2 % IL2 % IL1 pH 6.8 6.8 6.77.3 7.3 Viscosity 35 80 110 195 190 Degree of semi- C B A A Asolidification*⁾ *⁾C: Not semi-solidified B: A semi-solidified productwas observed on a nylon screen. A: Most was semi-solidified to give aresidue on a nylon screen.

Each food composition obtained was liquid.

Ascertaining the semi-solidification in an acidic condition, (1) thecomposition without sodium alginate was completely mixed with theartificial gastric juice and no solid was observed on a nylon screen.Each of the liquid food compositions (2) to (5) was semi-solidified inthe artificial gastric juice and gave a solid residue on a nylon screen.The pH, the viscosity before semi-solidification, and the degree ofsemi-solidification of each liquid composition are shown in Table 2.

Example 3

Based on the formulation described in Table 3, a liquid food compositioncontaining lysolecithin as an emulsifier was prepared in the followingmanner.

To 223 ml of distilled water, 3.6 g of lysolecithin (manufactured byTsuji Oil Mills Co., Ltd., product name: SLP-WhiteLyso, HLB value: about12) and 36 g of a fat (corn oil) were added, and while stirring, thewhole was homogenized (20 MPa) with a Manton Gaulin high-pressureemulsification equipment (Rannie 2000: manufactured by APV) to give 260ml of an emulsion.

Next, to 320 ml of distilled water, 173 ml of the emulsion was added.While stirring at an adequate speed, the distilled water and theemulsion were mixed, and then 7 g of sodium alginate was added. Next, adextrin powder and a soybean protein (manufactured by Fuji Oil Co.,Ltd.) were added until completely dissolved. Then, a phosphate, calciumcarbonate, magnesium carbonate, other minerals, and vitamins weresequentially added, and the whole was stirred. Then, distilled water wasadded to make the volume 700 ml and the mixture was homogenized with aManton Gaulin high-pressure emulsification equipment (for the firsttime: 20 MPa, for the second time: 48 MPa). Each soft bag (R1420H:manufactured by Meiwa Pax Co., Ltd.) was filled with 200 g of theprepared liquid food composition, and the whole was sterilized (121° C.,20 minutes) in an autoclave sterilizer.

The liquid food composition was a uniform liquid and the generation ofsolids and the separation of nutrient components were not observed. Theliquid food composition had a solidification ratio of 51%, an aggregateweight of 0.01 g, and a viscosity before semi-solidification of 77 cP.As shown in FIG. 2( a), the particle size distribution of the liquidfood composition had two peaks and the smaller peak was present in asection having a particle size of 3,000 nm or smaller (a particle sizeof 259 nm). The ultrasonic treatment reduced the frequency of the largerpeak and increased the frequency of the smaller peak present in thesection having a particle size of 3,000 nm or smaller. Evaluating eachpeak frequency increased or reduced before and after the ultrasonictreatment by the aforementioned equation ((peak frequency afterultrasonic treatment)/(peak frequency before ultrasonic treatment)×100),the smaller peak having the increased peak frequency was 137%(=12.32%/8.999%×100), while the larger peak having the reduced peakfrequency was 40% (=2.188%/5.482%×100).

As shown in FIG. 2( b), representing the particle size distribution ofthe liquid food composition as a distribution curve where the verticalaxis is passing particle integrated value (%) based on volume, theparticle size distribution curve had three inflection points of (1) at apassing particle integrated value of around 15.79% and a particle sizeof around 226 nm, of (2) at around 33.76% and around 877 nm, and of (3)at around 62.21% and around 5,876 nm. The passing particle integratedvalue of the inflection point (2) increased by 29% after the ultrasonictreatment as compared with that before the ultrasonic treatment, and theinflection point (2′) after the ultrasonic treatment was at around62.92% and around 877 nm.

The liquid food composition had less granular texture and goodswallowing feeling at the time of oral intake and was readily taken.

Example 4

Based on the formulation described in Table 3, a liquid food compositionwas prepared in a similar manner to that in Example 3 except thatsucrose laurate (manufactured by Mitsubishi-Kagaku Foods Corporation(product name: Ryoto Sugar Ester L-1695, HLB value: 16)) was used inplace of lysolecithin as the emulsifier.

The liquid food composition was a uniform liquid and the generation ofsolids and the separation of nutrient components were not observed. Theliquid food composition had a solidification ratio of 46%, an aggregateweight of 0.07 g, and a viscosity before semi-solidification of 161 cP.As shown in FIG. 3( a), the particle size distribution of the liquidfood composition had two peaks and the smaller peak was present in asection having a particle size of 3,000 nm or smaller (a particle sizeof 197 nm). The ultrasonic treatment reduced the frequency of the largerpeak and increased the frequency of the smaller peak present in thesection having a particle size of 3,000 nm or smaller. Evaluating eachpeak frequency increased or reduced before and after the ultrasonictreatment by the aforementioned equation, the smaller peak having theincreased peak frequency was (11.13/4.269×100) 261%, while the largerpeak having the reduced peak frequency was 38% (=4.882%/12.528%×100).

As shown in FIG. 3( b), representing the particle size distribution ofthe liquid food composition as a distribution curve where the verticalaxis is passing particle integrated value (%) based on volume, theparticle size distribution curve had three inflection points of (1) at apassing particle integrated value of around 5.70% and a particle size ofaround 172 nm, of (2) at around 19.30% and around 1,005 nm, and of (3)at around 50.44% and around 7,696 nm. The passing particle integratedvalue of the inflection point (2) increased by 37% after the ultrasonictreatment as compared with that before the ultrasonic treatment, and theinflection point (2′) after the ultrasonic treatment was at around56.11% and around 1,005 nm.

The liquid food composition had less granular texture and a littlethickness feeling at the time of oral intake but was readily taken.

Comparative Example 3

Based on the formulation described in Table 3, a liquid food compositionwas prepared in a similar manner to that in Example 3 except thatlecithin (manufactured by Wako, HLB value: about 3.5) was used in placeof lysolecithin as the emulsifier.

The liquid food composition had a solidification ratio of 36%, anaggregate weight of 0.3 g, and a viscosity before semi-solidification of190 cP. Comparing with the liquid food composition of Example 3, it hada lower solidification ratio and was liquid but in a non-uniform state,for example, the aggregates were visually observed, and also it had ahigh viscosity.

As shown in FIG. 4( a), the particle size distribution of the liquidfood composition had a peak in a section having a particle size of 3,000nm or larger. The ultrasonic treatment reduced the frequency of the peakbut no peak was observed in a section having a particle size of 3,000 nmor smaller.

As shown in FIG. 4( b), representing the particle size distribution ofthe liquid food composition as a distribution curve where the verticalaxis is passing particle integrated value (%) based on volume, theparticle size distribution curve had an inflection point at a passingparticle integrated value of around 42.43% and a particle size of around10,097 nm. The passing particle integrated value increased by 5% afterthe ultrasonic treatment as compared with that before the ultrasonictreatment, and the inflection point after the ultrasonic treatment wasat around 47.54% and around 5,867 nm.

The liquid food composition had granular texture and poor flowability atthe time of oral intake and was difficult to be taken.

In a similar manner to the weighing of the aggregates, the liquidcomposition was filtered and the generation of aggregates as the residuewas shown in FIG. 13. In the figure, the white parts are aggregates andthe figure reveals the generation of a large amount of aggregates.

Comparative Example 4

Based on the formulation described in Table 3, a liquid food compositionwas prepared in a similar manner to that in Example 3 except thatdiacetyl tartrate (manufactured by Taiyo Kagaku Co., Ltd. (product name:Sunsoft No. 641D, HLB value: 9.0)) was used in place of lysolecithin asthe emulsifier.

The liquid food composition had a solidification ratio of 41%, anaggregate weight of 0.14 g, and a viscosity before semi-solidificationof 182 cP. Comparing with the liquid food composition of Example 3, ithad a lower solidification ratio and was liquid but in a non-uniformstate, for example, the aggregates were visually observed, and also ithad a high viscosity. As shown in FIG. 5( a), the particle sizedistribution of the liquid food composition had a peak in a sectionhaving a particle size of 1,000 nm or larger. The ultrasonic treatmentreduced the frequency of the peak but no peak was observed in a sectionhaving a particle size of 1,000 nm or smaller.

As shown in FIG. 5( b), representing the particle size distribution ofthe liquid food composition as a distribution curve where the verticalaxis is passing particle integrated value (%) based on volume, theparticle size distribution curve had an inflection point at a passingparticle integrated value of around 40.75% and a particle size of around8,816 nm. The passing particle integrated value increased by 9% afterthe ultrasonic treatment as compared with that before the ultrasonictreatment, and the inflection point after the ultrasonic treatment wasat around 49.93% and around 5,867 nm.

The liquid food composition had granular texture and poor flowability atthe time of oral intake and was difficult to be taken.

In a similar manner to the weighing of the aggregates, the liquidcomposition was filtered and the generation of aggregates as the residuewas shown in FIG. 14. In the figure, dotted dark parts having anapproximately circular shape are aggregates, the aggregates are observedall over the nylon screen, and the figure reveals the generation of alarge amount of aggregates.

Comparative Example 5

Based on the formulation described in Table 3, a liquid food compositionwas prepared in a similar manner to that in Example 3 except thathexaglycerol tristearate (manufactured by Sakamoto Yakuhin Kogyo Co.,Ltd. (product name: TS-5S, HLB value: 7.0)) was used in place oflysolecithin as the emulsifier.

The liquid food composition had a solidification ratio of 44%, anaggregate weight of 0.13 g, and a viscosity before semi-solidificationof 185 cP. Comparing with the liquid food composition of Example 3, ithad a lower solidification ratio and was liquid but in a non-uniformstate, for example, the aggregates were visually observed, and also ithad a high viscosity. As shown in FIG. 6( a), the particle sizedistribution of the liquid food composition had a peak in a sectionhaving a particle size of 3,000 nm or larger. The ultrasonic treatmentreduced the frequency of the peak but no peak was observed in a sectionhaving a particle size of 3,000 nm or smaller.

As shown in FIG. 6( b), representing the particle size distribution ofthe liquid food composition as a distribution curve where the verticalaxis is passing particle integrated value (%) based on volume, theparticle size distribution curve had an inflection point at a passingparticle integrated value of around 47.17% and a particle size of around8,816 nm. The passing particle integrated value increased by 5% afterthe ultrasonic treatment as compared with that before the ultrasonictreatment, and the inflection point after the ultrasonic treatment wasat around 52.20% and around 5,122 nm.

The liquid food composition had granular texture and poor flowability atthe time of oral intake and was difficult to be taken.

The evaluation results of Examples 3 and 4 and Comparative Examples 3 to5 are listed in Table 4.

TABLE 3 Example Comparative Example Component composition (unit: g) 3 43 4 5 Water-soluble Sodium alginate 1.0 1.0 1.0 1.0 1.0 dietary fiberMinerals Calcium carbonate 0.190 0.190 0.190 0.190 0.190 Magnesiumcarbonate 0.140 0.140 0.140 0.140 0.140 Phosphate 0.3 0.3 0.3 0.3 0.3Other minerals 0.260 0.260 0.260 0.260 0.260 Plant protein Soybeanprotein 4.4 4.4 4.4 4.4 4.4 Emulsifier Lysolecithin 0.34 — — — — Sucroselaurate — 0.34 — — — Lecithin — — 0.34 — — Diacetyl tartrate — — — 0.34— Hexaglycerol tristearate — — — — 0.34 Fat Corn oil 3.4 3.4 3.4 3.4 3.4Carbohydrate Dextrin 12.0 12.0 12.0 12.0 12.0 Vitamins Vitamin premix0.170 0.170 0.170 0.170 0.170 Dietary fiber Dietary fiber 1.2 1.2 1.21.2 1.2 Distilled water Balance Balance Balance Balance Balance Total(volume) 100 ml 100 ml 100 ml 100 ml 100 ml

TABLE 4 Compar- Compar- Compar- Exam- Exam- ative ative ative Evaluationple 3 ple 4 Example 3 Example 4 Example 5 Solidification 51 46 36 41 44ratio (%) Aggregate (g) 0.01 0.07 0.3 0.14 0.13 Viscosity (cP) 77 161190 182 185 Granular texture Ab- Ab- Presence Presence Presence sencesence Easiness in intake A B C C C

(Passage Performance Evaluation in Tube Administration)

Using the liquid food compositions prepared in Examples 3 and 4 andComparative Example 3, the passage performance of each of the liquidfood composition at the time of tube administration was examined.

The tube used for the examination was a general purpose tube for enteralnutrient that had a tube size of 16 Fr and a tube length of 135 cm andequipped with a speed control throttle at a distance of 30 cm from anend of the tube. For the examination, a liquid food composition wastransferred to a plastic bottle (JMS feeding bottle), then the plasticbottle was placed so that the lower end of the bottle was positioned ata height of 150 cm from a floor, and an end of the tube was connected tothe lower end of the plastic bottle. In addition, the tube end oppositeto the end connected to the plastic bottle was placed at a height of 50cm from the floor. In the examination, the speed control throttle of thetube was adjusted so that distilled water would flow at a flow speed of200 g/minute, then each liquid food composition flowed, and the passageperformance was observed.

The results are shown in FIG. 7. The composition containing lysolecithincaused little aggregate clogging and had very good tube passageperformance. The liquid food composition containing sucrose lauratecaused little aggregate clogging and had good tube passage performance.As described above, the composition containing lysolecithin or sucroselaurate could be suitably used for tube administration. However, thecomposition containing lecithin caused aggregate clogging, had poor tubepassage performance, and finally did not flow. As described above, theliquid food composition containing lecithin could not be used for tubeadministration.

(Dependency Evaluation on Amount of Emulsifier Added)

Liquid food compositions were prepared in a similar manner to that inExample 1 except that lysolecithin was used as an emulsifier in variousamounts (mixing ratio of emulsifier/fat based on weight) as shown inTable 5. In the composition in Example 1, the amount of fat added waskept constant and the amount of the emulsifier was changed. The preparedliquid food compositions A to E were subjected to the same evaluation asthe above. The evaluation results are shown in Table 5.

Each of the liquid food compositions A and B had a solidification ratioof 41% or less, an aggregate weight of 0.13 g or more, and a viscosityof 158 cP or more. Comparing with the liquid food compositions C to E,each composition had a lower solidification ratio and was liquid but ina non-uniform state, for example, the aggregates were visually observed,and also each composition had a high viscosity. The particle sizedistributions of particles in the liquid food compositions A and B wereshown in FIGS. 8( a) and 9(a), respectively. Each particle sizedistribution of the liquid food compositions A and B had a peak in asection having a particle size of 3,000 nm or larger. The ultrasonictreatment reduced the frequency of the peak but no peak was observed ina section having a particle size of 3,000 nm or smaller.

The particle size distributions of the liquid food compositions A and Bare represented as distribution curves where the vertical axis ispassing particle integrated value (%) based on volume, and shown inFIGS. 8( b) and 9(b). The particle size distribution curve had only oneinflection point in each of the compositions A and B. Each liquid foodcomposition had granular texture and poor flowability at the time oforal intake and was difficult to be taken.

The liquid food compositions C to E were uniform liquids and thegeneration of solids and the separation of nutrient components were notobserved. The solidification ratio was 49% or more, the aggregate weightwas 0.03 g or less, and the viscosity was 133 cP or less. The particlesize distributions of particles in the liquid food compositions C to Eare shown in FIG. 10( a), FIG. 11( a), and FIG. 12( a), respectively.Each particle size distribution of the liquid food compositions C to Ehad two peaks, and the smaller peak was present in a section having aparticle size of 3,000 nm or smaller. The ultrasonic treatment reducedthe frequency of the larger peak and increased the frequency of thesmaller peak present in the section having a particle size of 3,000 nmor smaller. Evaluating each peak frequency increased or reduced beforeand after the ultrasonic treatment by the aforementioned equation, inthe liquid food composition C, the smaller peak having the increasedpeak frequency was 190% (=10.569%/5.618%×100), while the larger peakhaving the reduced peak frequency was 26% (=2.550%19.755%×100). In theliquid food composition D, the smaller peak having the increased peakfrequency was 140% (=12.32%18.999%×100), while the larger peak havingthe reduced peak frequency was 40% (=2.188%15.482%×100). In the liquidfood composition E, the smaller peak having the increased peak frequencywas 150% (=11.676%/7.871%×100), while the larger peak having the reducedpeak frequency was 36% (=2.819%/7.764%×100).

The particle size distributions of the liquid food compositions C to Eare represented as distribution curves where the vertical axis ispassing particle integrated value (%) based on volume, and shown in FIG.10( b), FIG. 11( b), and FIG. 12( b). In each of the compositions C toE, the particle size distribution curve had three inflection points, inC, of (1) at a passing particle integrated value of around 12.27% and aparticle size of around 226 nm, of (2) at around 30.12% and around 1,005nm, and of (3) at around 66.19% and around 6,720 nm, in D, of (4) ataround 16.58% and around 226 nm, of (5) at around 49.19% and around 766nm, and of (6) at around 76.27% and around 5,122 nm, and, in E, of (7)at around 15.63% and around 197 nm, of (8) at around 40.82% and around766 nm, and of (9) at around 71.13% and around 5,867 nm. The ultrasonictreatment shifted the inflection points (2, 5, and 8) of thecompositions C to E, in C, to (2′) at around 64.58% and around 877 nm,in D, to (5′) at around 70.79% and around 877 nm, and in E, to (8′) ataround 62.08% and around 766 nm after the ultrasonic treatment, and thevariations of the passing particle integrated values were 34% increasein C, 22% increase in D, and 21% increase in E as compared with thosebefore the ultrasonic treatment.

Each composition had less granular texture and good swallowing feelingat the time of oral intake and was readily taken.

In a similar manner to the weighing of the aggregates, the liquidcompositions D and E were filtered and the generations of aggregates asthe residue were shown in FIGS. 15 and 16, respectively. In the liquidcompositions D and E, the dotted dark parts are aggregates, but few darkparts were observed on the nylon screen, and it is clear that thegeneration of aggregates was effectively suppressed.

TABLE 5 Liquid food composition A B C D E Mixing ratio of 1/100 5/1007/100 10/100 20/100 emulsifier/fat Solidification 40 41 49 51 51 ratio(%) Aggregate (g) 0.194 0.131 0.03 0.009 0.016 Viscosity (cP) 158 165133 77 85 Change in particle Not Not Changed Changed Changed sizedistribution changed changed Granular texture Pres- Pres- AbsenceAbsence Absence ence ence Easiness in intake B B A A A

(Viscosity Measurement of Liquid Food Composition afterSemi-Solidification)

Based on the formulation described in Table 6, a liquid food compositionwas prepared.

To 650 ml of distilled water, 10 g of sodium alginate was added. Next, adextrin powder and a soybean protein powder were sequentially added anda fat (containing an emulsifier) was further added. Then, calciumcarbonate, magnesium carbonate, a phosphate, a potassium salt, a sodiumsalt, other minerals, and vitamins were added, and the whole wasstirred. The other minerals used were a mixture of a zinc-containingyeast, a copper-containing yeast, a manganese-containing yeast, achromium-containing yeast, a selenium-containing yeast, amolybdenum-containing yeast (these mineral-containing yeasts:manufactured by Medience Corporation), and ferric sodium citrate(manufactured by Ebisu Co., Ltd). Then, distilled water was added tomake the volume 1,000 ml and the mixture was homogenized with a MantonGaulin high-pressure emulsification equipment (Rannie 2000: manufacturedby APV) (for the first time: 20 MPa, for the second time: 48 MPa). Eachsoft bag (R1420H: manufactured by Meiwa Pax Co., Ltd.) were filled with200 g of the prepared liquid food composition, and the whole wassterilized (121° C., 20 minutes) in an autoclave sterilizer. The liquidfood composition had a pH of 6.7 before pH adjustment.

Viscosity was determined with a Brookfield viscometer. Into a glasscontainer having an inner diameter of 60 mm, 200 ml of the liquid foodcomposition was charged, the pH of the composition was adjusted to a pHof 4.5 to 5.5 using 5N HCl (extremely gently stirred for preventing asolidified product from being destroyed), and the composition was leftfor 5 minutes. After the standing, the measurement was carried out in acondition at a rotation speed of 12 revolutions per minute and a holdingtime of 1 minute to read a measured value. The rotor type was properlychanged as shown in Table 7 depending on the viscosity of a sample.

The measured results are shown in Table 7. As shown in Table 7, theliquid food composition had an increased viscosity of 1,000 cP or morein an acidic region. In particular, at a pH of 4.5, the viscosity wasincreased to 10,000 cP or more.

TABLE 6 Component Formulation [g] Water-soluble Sodium alginate 1.0dietary fiber Minerals Calcium carbonate 0.180 Magnesium carbonate 0.140Phosphate 0.6 Potassium salt 0.440 Sodium salt 0.170 Other minerals0.062 Plant protein Soybean protein 4.4 Emulsifier Lysolecithin 0.34 FatCorn oil 3.4 Carbohydrate Dextrin 12.0 Vitamins Vitamin premix 0.060Dietary fiber Dietary fiber 3.8 Distilled water Balance Total (volume)100 ml

TABLE 7 pH at the time of preparation Rotor No. Viscosity (cP) 5.5 21260 5.0 3 8950 4.5 4 10,000 or more

1. A liquid food composition being semi-solidified in an acidic region,the liquid food composition comprising: a water-soluble dietary fiber(a); a metal compound (b) containing a necessary mineral component forhumans and not causing gelation of the water-soluble dietary fiber in aneutral region; a protein (c); and an emulsifier (d), the liquid foodcomposition including particles having a particle size distribution withtwo or more peaks in the neutral region.
 2. The liquid food compositionaccording to claim 1, wherein the liquid food composition in asemi-solidified state has a viscosity of 1,000 cP or more in the acidicregion.
 3. The liquid food composition according to claim 2, wherein atleast one peak of two or more peaks present in the particle sizedistribution of the particles is present at a particle size of 3,000 nmor smaller.
 4. The liquid food composition according to claim 1, whereinultrasonic treatment of the liquid food composition increases afrequency of the at least one peak present at a particle size of 3,000nm or smaller after the ultrasonic treatment as compared with thatbefore the ultrasonic treatment and reduces a frequency of at least onepeak other than the peak having the increased frequency after theultrasonic treatment as compared with that before the ultrasonictreatment.
 5. The liquid food composition according to claim 1, wherein,in the at least one peak having the increased frequency in the particlesize distribution of particles after the ultrasonic treatment, theincreased frequency is 105% or more with respect to the frequency in theparticle size distribution of particles before the ultrasonic treatmentand, in the at least one peak having the reduced frequency in theparticle size distribution of particles after the ultrasonic treatment,the reduced frequency is 60% or less with respect to the frequency inthe particle size distribution of particles before the ultrasonictreatment.
 6. A liquid food composition being semi-solidified in anacidic region, the liquid food composition comprising: a water-solubledietary fiber (a); a metal compound (b) containing a necessary mineralcomponent for humans and not causing gelation of the water-solubledietary fiber in a neutral region; a protein (c); and an emulsifier (d),the liquid food composition having a distribution curve of two or moreinflection points, when representing a particle size distribution ofparticles included in the liquid food composition in the neutral region,as a distribution curve of a passing particle integrated value based onvolume.
 7. The liquid food composition according to claim 6, wherein theliquid food composition in a semi-solidified state has a viscosity of1,000 cP or more in the acidic region.
 8. The liquid food compositionaccording to claim 7, wherein at least one of the inflection points inthe distribution curve is present in a particle size section having aparticle size of 3,000 nm or smaller.
 9. The liquid food compositionaccording to claim 6, wherein at least one of the inflection points inthe distribution curve is present in a particle size section having aparticle size of 2,000 nm or smaller, and ultrasonic treatment of theliquid food composition increases a passing particle integrated valuecorresponding to the at least one inflection point, present in aparticle size section having a particle size of 2,000 nm or smaller, by5% or more after the ultrasonic treatment as compared with that beforethe ultrasonic treatment.
 10. The liquid food composition according toclaim 6, wherein at least one of the inflection points in thedistribution curve is present in a particle size section having aparticle size of 2,000 nm or smaller, and ultrasonic treatment of theliquid food composition shifts a passing particle integrated valuecorresponding to the at least one inflection point, present in aparticle size section having a particle size of 2,000 nm or smaller, toa section having a passing particle integrated value of 25% or moreafter the ultrasonic treatment as compared with that before theultrasonic treatment.
 11. The liquid food composition according to claim1, wherein aggregate weight determined by a measurement method below is0.1 g or less, aggregate weight: 200 ml of the liquid food compositionis filtered using a 264-mesh nylon screen of which dry weight (W1) ispreliminarily weighed; the nylon screen after the filtration is dried at60° C. for 1 hour and then cooled; a dry weight (W2) of the screen isweighed; and difference (W2−W1) between the dry weights before and afterthe filtration is calculated to determine weight of an aggregateobtained as a residue.
 12. The liquid food composition according toclaim 1, wherein the water-soluble dietary fiber (a) is alginic acidand/or a salt thereof.
 13. The liquid food composition according toclaim 1, wherein the protein (c) is a plant protein derived from aplant.
 14. The liquid food composition according to claim 13, whereinthe plant protein is a bean-derived protein.
 15. The liquid foodcomposition according to claim 14, wherein the bean-derived protein is asoybean protein and/or a hydrolysate thereof.
 16. The liquid foodcomposition according to claim 1, wherein the metal compound (b)containing a necessary mineral component for humans and not causinggelation of the water-soluble dietary fiber in the neutral region is atleast one compound selected from the group consisting of a metalcompound having poor solubility in the neutral region, a metal compoundincluded in a microorganism such as a yeast, and a metal compoundincluded in a microcapsule.
 17. The liquid food composition according toclaim 16, wherein the metal compound (b) containing a necessary mineralcomponent for humans and not causing gelation of the water-solubledietary fiber (a) in the neutral region is a calcium compound havingpoor solubility in the neutral region and/or a magnesium compound havingpoor solubility in the neutral region.
 18. The liquid food compositionaccording to claim 17, wherein the calcium compound (b) having poorsolubility in the neutral region is at least one compound selected fromthe group consisting of calcium citrate, calcium carbonate, calciumdihydrogen pyrophosphate, tricalcium phosphate, calcium monohydrogenphosphate, calcium stearate, and calcium silicate.
 19. The liquid foodcomposition according to claim 17, wherein the magnesium compound (b)having poor solubility in the neutral region is at least one compoundselected from the group consisting of magnesium carbonate, magnesiumoxide, magnesium stearate, and trimagnesium phosphate.
 20. The liquidfood composition according to claim 16, wherein the metal compound (b)containing a necessary mineral component for humans and not causinggelation of the water-soluble dietary fiber (a) in the neutral region isat least one selected from the group consisting of a zinc-containingyeast, a copper-containing yeast, a manganese-containing yeast, achromium-containing yeast, a selenium-containing yeast, and amolybdenum-containing yeast.
 21. The liquid food composition accordingto claim 16, wherein the metal compound (b) containing a necessarymineral component for humans and not causing gelation of thewater-soluble dietary fiber (a) in the neutral region is ferric sodiumcitrate.
 22. The liquid food composition according to claim 1, whereinthe emulsifier (d) is an emulsifier having an HLB value of more than 9.23. The liquid food composition according to claim 22, wherein theemulsifier (d) is lysolecithin and/or a sucrose fatty acid estercomposed of a fatty acid monoester having a carbon number of 18 or less.24. The liquid food composition according to claim 22, wherein theemulsifier (d) is lysolecithin and/or sucrose laurate.
 25. The liquidfood composition according to claim 1, further comprising a fat (e). 26.The liquid crystal food composition according to claim 25, wherein theemulsifier (d) and the fat (e) are mixed in a ratio ((d)/(e), based onweight) of more than 5/100 and 30/100 or less.
 27. The liquid foodcomposition according to claim 1, wherein at least the components (a) to(d) are filled in a container as a one-pack type product.
 28. The liquidfood composition according to claim 1, further comprising a nutrientcomponent (f).
 29. The liquid food composition according to claim 1,sustaining a liquid state during storage.
 30. The liquid foodcomposition according to claim 1, wherein the liquid food composition issemi-solidified in an acidic environment in a stomach and has an effectof preventing gastroesophageal reflux disease, aspiration pneumonia,diarrheal disease, leakage from a fistula, or the like.
 31. The liquidfood composition according to claim 1, wherein the liquid foodcomposition is semi-solidified in an acidic environment in a stomach andhas an effect of relieving feeling of hunger.
 32. The liquid foodcomposition according to claim 1, wherein the liquid food composition issemi-solidified in an acidic environment in a stomach and has an effectof suppressing sudden increase in blood glucose level.
 33. An enteralnutrition food comprising the liquid food composition according toclaim
 1. 34. An oral nutrition food comprising the liquid foodcomposition according to claim
 1. 35. A diet food comprising the liquidfood composition according to claim 1.